WEll sad to say there isn't realy a good place to buy africans. I would say the best place is probably Big al's, another place used to be Aquarium illusions but they dont' really keep much fresh water anymore. Big al's has the best selection but at times the fish dont' always look so good.
I dont' really buy my fish at any stores anymore. I have found that i can find pretty much any fish i want through the aquarium club and the clubs auction. I haven't bought a fish from a store since i joined.
What sort of fish are you looking for?