Trying to buy a new computer..

[Fiorana]

If you're looking for the cheapest PC that can easily handle this game, I'd take a good look at this build. It's $100 cheaper than the ones you listed in the OP and will perform better too.

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: AMD FX-6300 3.5GHz 6-Core Processor ($116.58 @ Microcenter)
Motherboard: Asus M5A97 LE R2.0 ATX AM3+ Motherboard ($54.99 @ Newegg)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory ($49.99 @ Newegg)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($54.99 @ Newegg)
Video Card: MSI Radeon HD 7850 2GB Video Card ($119.99 @ Newegg)
Case: Thermaltake Commander MS/I Snow Edition (White/Black) ATX Mid Tower Case ($49.99 @ Mwave)
Power Supply: Corsair Builder 600W 80+ Bronze Certified ATX Power Supply ($29.99 @ Newegg)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) ($89.00 @ Amazon)
Total: $565.52
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-12-02 05:52 EST-0500)

If you still have some room left in your budget, upgrade the GPU to a GTX 660, GTX 760, or Radeon R9 270X

I approve of this build, although I would get an aftermarket cpu cooler though.