WinPower are defintely the bottom of the barrel. It might be better than what you have now but I doubt the amperage will be enough. Even something like: http://www.newegg.com/Product/Product.aspx?Item=N82E16817371006
would be better. You should have around18amps on the 12+ for your card (the one I posted only has 17a). That's more important than the wattage.
My PSU was $150. It's one thing that can last a long time and reuse with multiple PC upgrades (unlike most other parts in your PC).