I have the controller for it but it didn't come with the battery pack. There is one listed on OKorder for $40 and I heard there is a non-official pack that will work. Any help would be great.
Depending on the State and city you live in there are still game stores (other than gamestop and EB) that carry a wide variety of used merchandise for all platforms. This includes games, systems and all accessories. Try looking up stores online or in the yellowpages.