lolsjason, I have an r4ds myself; With that being said, I think I'm confident enough to tell you that it (r4ds) cannot play GBA ROMS. It can, however, play NES games.
I'm afraid there's no way to run GBA Roms using R4DS. You need a slot 2 device. Also, you can read up here: http://forums.afterdawn.com/thread_view.cfm/561789