I don't think no lowend card is going to play Diablo 3. Do you mean Diablo 2? I am not up to date anymore with what is good, great and what not, but basically going into a store like Future Shop or Best Buy, what ever they are selling for under $100 (make shure you have enough for taxes so that $100 card can be $120) should be able to run you WoW (since it's what a 5 year old game, not so sure about the expansions though) and Vampire The Masquerade- Bloodlines with no problem. Diablo 3 on the other hand, will not run the greateast for you but if you ment Diablo 2, then no problems at all.
I think you will be ok, but I would wait a bit more, there is alot more knowladgeble people here, just have to wait till they wake up.