You don't need a $300 graphics card to do those things or play those games. A card under $200 is perfectly fine for those games. I'd suggest an Nvidia GTX 750 Ti. It's the perfect balance between low power consumption, and high performance, even to this day, when there are newer cards available. On the AMD side an R7 260X would be the equivalent performance as the 750 Ti, though it might use up a bit more power.
Check out this graphics card hierarchy list and you can make an informed decision as to what to buy:
GPU Hierarchy - Comparison of Graphics Cards for Gaming
http://www.tomshardware.com/reviews/gpu-hierarchy,4388.html