Do you have any minimum or recommended requirements for your needs, are your applications have special requirements in terms of rendering, or does it state anywhere which video card suppose to be?
Sapphire 7750 DDR5 http://www.newegg.com/Product/Product.aspx?Item=N82E168... will work without upgrading power supply. How much more you need. Review feedback on newegg, maybe it would be enough for you. Power supply alone wouyld cost you around 60-80 USD, so for 200 USD 7750 is the best choice.