[duo797]

Even if you have to post in romaji, I think you'd be more likely to receive help if you posted the entire song and bolded the words you're confused about. Also, agerereba isn't the potential form of anything. The potential form, first of all, is agerareru (or if you shorten it, which it probably would be in a song, agereru). I'm almost positive the -ba form is a conditional, and you would drop the last -ru and add -ba anyways, so I think you might have made a mistake in copying, but I could be wrong.

Edit: This should also be posted in the stickied thread at the top of the forum, not this one. If you do post the full song lyrics, post them in that thread, not this one.