Just sell the parts you have for a few bucks because they are no good to you.
This is the best you can do for $730. The GTX750 ti is a good bit better than the 260x
PCPartPicker part list:
http://pcpartpicker.com/p/3wMSW
Price breakdown by merchant: http://pcpartpicker.com/p/3wMSW/by_merchant/
Benchmarks: http://pcpartpicker.com/p/3wMSW/benchmarks/
CPU: Intel Core i3-4130 3.4GHz Dual-Core Processor ($118.97 @ OutletPC)
Motherboard: Gigabyte GA-B85M-D2V Micro ATX LGA1150 Motherboard ($47.79 @ Newegg)
Memory: G.Skill Ares Series 8GB (2 x 4GB) DDR3-1600 Memory ($68.99 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($54.98 @ OutletPC)
Video Card: EVGA GeForce GTX 750 Ti 2GB Video Card ($144.99 @ NCIX US)
Case: Antec One ATX Mid Tower Case ($34.99 @ NCIX US)
Power Supply: SeaSonic 350W 80+ Bronze Certified ATX Power Supply ($41.99 @ Mwave)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer ($15.98 @ OutletPC)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) ($89.98 @ OutletPC)
Monitor: LG 22EN43T-B 21.5" Monitor ($109.99 @ Newegg)
Total: $728.65
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-04-22 22:41 EDT-0400)