my database is too big
 

According to my control panel, I have a 1.39gb date usage and 1.22gb attachment usage. I only set up one database so I assume this is all on one database. I need to switch hosts so I can upgrade b/c my current one is still on php4 instead of php5 with no plans on upgrading. Is there a way to break apart the database into smaller ones? Most ISPs I've looked at have max dbase size limits. What do I need to do?