You will need to find the apple.dbx file. Copy the apple.dbx file to an empty folder. It contains all of the emails stored in your apple folder.
Go to this site: http://www.oehelp.com/DBXtract/Default.aspx and download DBXtract. Save it to the folder you copied your apple.dbx file to. Run the program in recover mode and it should get back most of your emails.