By Sears do you mean Craftsman?
What's the model#?
If you want new batteries you could probably have them rebuilt at Interstate Battery or Batteries Plus. They probably use higher quality packs.
If there is a conversion kit for your drill you may be able to buy NiMH or LiIon batteries to replace your current ones. Of course, this would also require buying a new charger. Considering the low cost of the drill and the price of a new Li-Ion drill from Makita or Milwaukee, it's probably more cost effective to just buy a new one. Replacement batteries for my Porter Cable are $90, when it dies I'm getting a Li-Ion.
