Those games aren't all that demanding graphically but you could do with a decent CPU and RAM.
PCPartPicker part list:
http://pcpartpicker.com/p/rCLqMp
Price breakdown by merchant: http://pcpartpicker.com/p/rCLqMp/by_merchant/
CPU: Intel Xeon E3-1231 V3 3.4GHz Quad-Core Processor ($242.99 @ SuperBiiz)
CPU Cooler: Cooler Master Hyper TX3 54.8 CFM Sleeve Bearing CPU Cooler ($19.98 @ OutletPC)
Motherboard: ASRock H97M-ITX/AC Mini ITX LGA1150 Motherboard ($72.98 @ Newegg)
Memory: G.Skill Ares Series 16GB (2 x 8GB) DDR3-1600 Memory ($84.99 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($46.89 @ OutletPC)
Video Card: EVGA GeForce GTX 750 Ti 2GB Superclocked Video Card ($119.99 @ Newegg)
Power Supply: Antec Green 450W 80+ Bronze Certified ATX Power Supply ($32.98 @ Newegg)
Operating System: Microsoft Windows 8.1 OEM (64-bit) ($86.98 @ OutletPC)
Other: RAIJINTEK Metis - Green ($49.99)
Total: $757.77
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-07-07 17:59 EDT-0400
That should do a good job and has the added bonus of being small. (assuming you want a small build)