That's a very low budget to build any satisfactory gaming rig.. The best you can do is secure this budget to get yourself a processor, motherboard, ram, case, power supply, hard drive and optical drive.. Assemble cash separately to get a video card..
Athlon II X3 445
MSI 880GM-E43 Motherboard
Corsair XMS3 4GB (2 x 2GB) DDR3 1600 MHz
Seasonic S12II 520
Samsung Spinpoint F3 500 GB