If your purpose is gaming, spend what you can on the graphics card, it is the real engine of gaming.
In this case, the 7850 is a stronger card, so the $33 will be well spent.
Do not be influenced by the amount of Vram, or lack thereof.
It really makes negligible difference in anything but the highest end rigs.
Someone from their live chat support recommended the MSI GeForce GTX 560 Ti TWINFRZR II because it has better cooling and is overclocked. He also said both cards were approximately the same strength.