I would save some of that money and maybe go with a GTX 960 2GB or an RX 550 at the most. The CPU is not the greatest. It can get beaten by ones from from 4 years earlier. than it (if not more).
On the other hand, I do have some systems laying around with a Phenom II X4 840 and a RX 550 2GB and they are often bottlenecked by the GPU. The Phenom II X4 840 is slightly better than your CPU based on some research I just did.
If you really want to stretch your $200 for a GPU, go for a GTX 970 when on eBay goes below $200 (which they do), or bid on one until you win it for that price. But I don't recommend it.