good base i changed two parts and stayed under 500.00 the two parts was i swapped out your cpu for a four core cpu without the gpu built in. and then put in a high end gpu that on sale for 20 more then the card you listed.
PCPartPicker part list:
http://pcpartpicker.com/p/28Mis
Price breakdown by merchant: http://pcpartpicker.com/p/28Mis/by_merchant/
Benchmarks: http://pcpartpicker.com/p/28Mis/benchmarks/
CPU: AMD Athlon II X4 740 3.2GHz Quad-Core Processor ($74.99 @ Newegg)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($29.98 @ OutletPC)
Motherboard: MSI FM2-A85XA-G65 ATX FM2 Motherboard ($64.99 @ Newegg)
Memory: A-Data XPG Gaming Series 8GB (1 x 8GB) DDR3-1600 Memory ($59.99 @ Newegg)
Storage: Western Digital Caviar Blue 500GB 3.5" 7200RPM Internal Hard Drive ($54.99 @ Microcenter)
Video Card: MSI Radeon HD 7870 GHz Edition 2GB Video Card ($129.99 @ Newegg)
Wireless Network Adapter: Asus USB-N10 802.11b/g/n USB 2.0 Wi-Fi Adapter ($17.77 @ B&H)
Case: Raidmax ATX-249B (Black) ATX Mid Tower Case ($19.99 @ Newegg)
Power Supply: EVGA 600B 600W 80+ Bronze Certified ATX Power Supply ($34.99 @ Microcenter)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer ($16.99 @ Microcenter)
Total: $494.67
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-11-26 01:08 EST-0500)