I was using a 660ti with a II x4 640 just fine with some small cpu bottlenecks, but i was mostly getting the same preformance as everyone else.
http://www.cpu-world.com/Compare/73/AMD_Athlon_II_X2_220_vs_AMD_Athlon_II_X4_640.html
it really depends on what you play but it should be kinda fine, but that cpu is pretty old... ofcorse if you have the option, buy the gpu, see if it works than upgrade the cpu if it doesn't.