Here's a quick, rough compilation which should be able to run both the current and next version of AH recently well. It's also easily upgradable if needed. I don't know much of brands, these are from reputable makers though. Notice that if you already have a Windows7 license just lying around, i.e. not installed in any computer, the total would fit your budget.
PCPartPicker part list:
http://pcpartpicker.com/p/PmjnxrCPU: Intel Pentium G3258 3.2GHz Dual-Core Processor ($59.99 @ Newegg) Notice: Overclocking is a
must with this one, getting the same performance of a stock CPU would multiply the price.
CPU Cooler: Arctic Cooling Alpine 11 Plus Fluid Dynamic Bearing CPU Cooler ($8.50 @ SuperBiiz) Cheap as soap, and silent as a whisper.
Motherboard: MSI Z97 PC MATE ATX LGA1150 Motherboard ($68.20 @ SuperBiiz)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory ($29.99 @ Newegg)
Storage: Seagate Constellation ES.3 1TB 3.5" 7200RPM Internal Hard Drive ($76.50 @ SuperBiiz)
Video Card: EVGA GeForce GTX 960 2GB SuperSC ACX 2.0+ Video Card ($169.99 @ Amazon)
Case: Cougar Solution 2 ATX Mid Tower Case ($39.10 @ SuperBiiz)
Power Supply: SeaSonic 650W 80+ Gold Certified Semi-Modular ATX Power Supply ($59.99 @ Newegg)
Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($14.99 @ Newegg)
Operating System: Microsoft Windows 7 Professional SP1 OEM (64-bit) ($141.98 @ OutletPC)
Total: $669.23Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-11-27 03:04 EST-0500