PCPartPicker part list:
http://pcpartpicker.com/p/1egWi
Price breakdown by merchant: http://pcpartpicker.com/p/1egWi/by_merchant/
Benchmarks: http://pcpartpicker.com/p/1egWi/benchmarks/
CPU: AMD FX-6300 3.5GHz 6-Core Processor ($119.99 @ Newegg)
Motherboard: Gigabyte GA-970A-DS3 ATX AM3+ Motherboard ($69.98 @ Newegg)
Video Card: Sapphire Radeon HD 7850 1GB Video Card ($139.99 @ Newegg)
Case: Cooler Master Elite 431 Plus (Black) ATX Mid Tower Case ($49.99 @ Newegg)
Power Supply: Corsair CX 500W 80 PLUS Bronze Certified ATX12V Power Supply ($39.99 @ Newegg)
Total: $391.94
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-07-07 20:18 EDT-0400)
7850 is superior to the 7770 you selected, 6300 is better than the 4300, I prefer Gigabyte for low end boards, and 350d is too expensive for a build like yours... Hope this helps