PCPartPicker part list:
http://pcpartpicker.com/p/34q1Q
Price breakdown by merchant: http://pcpartpicker.com/p/34q1Q/by_merchant/
Benchmarks: http://pcpartpicker.com/p/34q1Q/benchmarks/
CPU: AMD Athlon II X4 645 3.1GHz Quad-Core Processor ($75.12 @ SuperBiiz)
Motherboard: Gigabyte GA-78LMT-S2 Micro ATX AM3+ Motherboard ($42.99 @ Amazon)
Memory: A-Data XPG V1.0 4GB (1 x 4GB) DDR3-1600 Memory ($32.99 @ Newegg)
Video Card: Zotac GeForce GTX 650 Ti 1GB Video Card ($119.98 @ SuperBiiz)
Power Supply: Antec 450W ATX Power Supply ($34.99 @ Amazon)
Total: $306.07
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-03-05 01:46 EST-0500)
I didnt add a case as u already have a 1
later u can add same stick of 4gb
and if want to upgrade cpu upgrade with fx series in future
650ti is good to play games
check game debate site for card review and cpu review