If u want the bottom 2 panels to be on the same level, u can try setting ur content pane to use the BorderLayout and the adding the 3 panels to it with BorderLayout.NORTH(for the TOP panel), BorderLayout.EAST(RIGHT panel) and BorderLayout.WEST(for LEFT panel).
Don't know if this is what ur looking for, maybe u could describe more on ur layout with a sample image or something?
By default a panel is the preferred size of all the children added to the panel. If you want to override this then you need to use setPreferredSize() on the panel.
Read the Swing tutorial on [url http://java.sun.com/docs/books/tutorial/uiswing/layout/visual.html]How to Use Layout Managers[/url] for more information.