Video Card:Gigabyte Radeon R7 260X 2GB Video Card ($146.81 @ NCIX US) Total: $146.81 (Prices include shipping, taxes, and discounts when available.) (Generated by PCPartPicker 2013-12-21 03:24 EST-0500)
With this gpu you should be able to play most on medium.
You won't be running AC4 at even high settings, the game runs really bad on weaker systems so you'd be lucky if you can play it smoothly at low-medium at 30FPS