Como alterar o tamanho

import java.awt.*;
import java.awt.event.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Vector;

import javax.swing.*;
import javax.swing.table.DefaultTableModel;


public class admp extends JFrame implements ActionListener{
	Connection Con;
	Statement Stm;
	String strSQL = "";
	    
	JTable Grade, Grade1, Grade2;
	JPanel P1, P2,P3;
	
	String strMsg = "";
	
    public admp(){		
    	admps();
    	int intRes = Conectar();
		if(intRes == 0){
			show();
	        Consultar_Dados();
			return;
		}
	if(intRes == 1) strMsg = "Driver Não Encontrado";
	if(intRes == 2) strMsg = "Erro de Conexão com o Banco de Dados";
	JOptionPane.showMessageDialog(null, strMsg,"Erro",0);
	System.exit(0);
    }
    
    public void admps(){
		setTitle("Administração");
		setSize(new Dimension(640,425));
		setExtendedState(MAXIMIZED_BOTH);
		ImageIcon icone = new ImageIcon("C:\\Documents and Settings\\Administrador\\Desktop\\Rodrigo\\Java\\icoprogram.png");
		setIconImage(icone.getImage());
	    getRootPane().setWindowDecorationStyle(JRootPane.NONE);
		getContentPane().setLayout(new BorderLayout());
		    
        P1 = new JPanel();
        P1.setLayout(new BorderLayout());
        P1.setOpaque(true);
        
        Grade = new JTable();
		Grade.setFocusable(false);
		Grade.setEnabled(false);
		//Grade.setBounds(0,100,50,200);
		P1.add(new JScrollPane(Grade),BorderLayout.CENTER);
		P1.add(new JLabel("Ultimos 40 Carros Cadastrados"),BorderLayout.NORTH);
		add(P1,BorderLayout.WEST);
    
		P2 = new JPanel();
        P2.setLayout(new BorderLayout());
        P2.setOpaque(true);
        
        Grade1 = new JTable();
		Grade1.setFocusable(false);
		Grade1.setEnabled(false);
		//Grade.setBounds(0,100,50,200);
        P2.add(new JLabel("Ultimos 40 Acessos"),BorderLayout.NORTH);
		P2.add(new JScrollPane(Grade1),BorderLayout.CENTER);
		add(P2,BorderLayout.EAST);
    
		P3 = new JPanel();
        P3.setLayout(new BorderLayout());
        P3.setOpaque(true);
       
        Grade2 = new JTable();
		Grade2.setFocusable(true);
		Grade2.setEnabled(false);
        P3.add(new JLabel("Média Diária"),BorderLayout.NORTH);  
		P3.add(new JScrollPane(Grade2),BorderLayout.CENTER);
		add(P3,BorderLayout.CENTER);
		
    }
    
    public int Conectar(){
 		try{
 			Class.forName("com.mysql.jdbc.Driver");
 		}
 		catch(ClassNotFoundException cnfe){
 			return 1;
 		}
 		try{
 			Con = DriverManager.getConnection("jdbc:mysql://localhost:3306/estacionamento","root","011095");
 			Stm = Con.createStatement();
 			return 0;
 		}
 		catch(SQLException sqle){
 			return 2;
 		}
 	}
 	public void Desconectar(){
 		try{
 		Stm.close();
 	}
 		catch(SQLException sqle){}
 		
 	}
    
    public void Consultar_Dados()
	{
		String strSQL = "";
		strSQL = "Select nomecliente as Nome_do_Cliente,placacarro as Placa_do_Carro,nomemodel as Modelo_do_Carro from cadastrocarro order by codigo DESC LIMIT 40";
		try
		{
			ResultSet rs = Stm.executeQuery(strSQL);
			ResultSetMetaData rsmd = rs.getMetaData();
			// Criando as Colunas do Grid
			String[] col = new String[rsmd.getColumnCount()];
			for (int i=0;i< rsmd.getColumnCount();i++)
			{
				col[i] = rsmd.getColumnLabel(i+1);
			}
			// Adicionando os dados no vetor para exibir no Grid
			Vector vt = new Vector();
			while (rs.next())
			{
				Object[] row = new Object[rsmd.getColumnCount()];
				for (int i=0;i< rsmd.getColumnCount();i++)
					row[i] = rs.getObject(i+1);
				vt.add(row);
			}
			// Exibindo o Grid
			Object[][] lin = (Object[][])vt.toArray(new Object[0][0]);
			Grade.setModel(new DefaultTableModel(lin,col));
			
		}
		catch (SQLException sqle)
		{
			strMsg = "Ocorreu erro ! \nCodigo:" + sqle.getErrorCode() + "\nMensagem: " + sqle.getMessage();
			JOptionPane.showMessageDialog(null,strMsg,"Erro",0);
		}
		
		strSQL = "Select login as Usuario, data as Data from controlacess order by data DESC LIMIT 40";
		try
		{
			ResultSet rs1 = Stm.executeQuery(strSQL);
			ResultSetMetaData rsmd1 = rs1.getMetaData();
			// Criando as Colunas do Grid
			String[] col = new String[rsmd1.getColumnCount()];
			for (int i=0;i< rsmd1.getColumnCount();i++)
			{
				col[i] = rsmd1.getColumnLabel(i+1);
			}
			// Adicionando os dados no vetor para exibir no Grid
			Vector vt = new Vector();
			while (rs1.next())
			{
				Object[] row = new Object[rsmd1.getColumnCount()];
				for (int i=0;i< rsmd1.getColumnCount();i++)
					row[i] = rs1.getObject(i+1);
				vt.add(row);
			}
			// Exibindo o Grid
			Object[][] lin = (Object[][])vt.toArray(new Object[0][0]);
			
			Grade1.setModel(new DefaultTableModel(lin,col));
		}
		catch (SQLException sqle)
		{
			strMsg = "Ocorreu erro ! \nCodigo:" + sqle.getErrorCode() + "\nMensagem: " + sqle.getMessage();
			JOptionPane.showMessageDialog(null,strMsg,"Erro",0);
		}

		
		try
		{
			strSQL = "Select sum(saldopos) as Saldo_Positivo, sum(saldoneg) as Saldo_Negativo, sum(saldopos)+(saldoneg) as Saldo_Total from cadastrocarro";
			ResultSet rs2 = Stm.executeQuery(strSQL);
			ResultSetMetaData rsmd2 = rs2.getMetaData();
			// Criando as Colunas do Grid
			String[] col = new String[rsmd2.getColumnCount()];
			for (int i=0;i< rsmd2.getColumnCount();i++)
			{
				col[i] = rsmd2.getColumnLabel(i+1);
			}
			// Adicionando os dados no vetor para exibir no Grid
			Vector vt = new Vector();
			while (rs2.next())
			{
				Object[] row = new Object[rsmd2.getColumnCount()];
				for (int i=0;i< rsmd2.getColumnCount();i++)
					row[i] = rs2.getObject(i+1);
				vt.add(row);
			}
			// Exibindo o Grid
			Object[][] lin = (Object[][])vt.toArray(new Object[0][0]);
			
			Grade2.setModel(new DefaultTableModel(lin,col));
		}
		catch (SQLException sqle)
		{
			strMsg = "Ocorreu erro ! \nCodigo:" + sqle.getErrorCode() + "\nMensagem: " + sqle.getMessage();
			JOptionPane.showMessageDialog(null,strMsg,"Erro",0);
		}
	}
 	
    }
    
	public static void main(String[] args) {
		new admp();
	}

}