Upgrade for my video card?

I currently have an ATI Radeon HD 6450, which I've been told is not really a great card. I primarily play WoW, Starcraft 2, Dragon Age, etc. and I want them to be able to run at higher settings yet still maintain high FPS. Without breaking the bank, what are some good card upgrades that won't become outdated quickly?|||5770, is around 99-120$ and is 500% better(NOT A JOKE). If you want to spend less or don't have at least a 400w power supply or space, go with the hd 5750, which is like 300% better(still not a joke).