As of right now I have a AMD A4-4300M APU. Winning one of AMD's new GPU would be great, because I will be getting a Dell Optiplex with a Sandy Bridge CPU. I'm not sure if the CPU will make the Polaris use its full potential, but it's a great start for a Gaming PC around $250 maybe.
Dell OptiPlex 790 MT $130
A Corsair Powersupply around $50
Anything else and is this a good way to go about a budget build?