I know its kind of late (So much for being helpful) but Its worth a shot. The GBA and SP are reigion free, but since you imported, NOA will probably not have your SP in their database, hence no warranty. They will
A) Send you to the nearest authorized Nintendo repair center and will have to pay whatever fee the shop charges.
B) (Doubtful but possible) will ask you to send it and replace it with an American one, but since it isn't under a U.S warranty, you might have to pay for shipping and the unit (Maybe 70 dollars or so.)
Either way, check Nintendo's official website for info. Hope that helps you out. Though IMHO, you could've waited the extra week or so. But to each their own hmmm?