Should work just fine. I'm sure others will come in here telling you to go with the 7850 or something but they are about the same so pick based off what you prefer Nvidia or AMD. Although i think the 7850 comes with a game right now.
would be a decent upgrade but make sure the card isn't too long to fit in the case. if you can remove any of those drive bays it might help.
card is 10-3/4 inches long.
I hadn't thought about that, so thanks for your reply! I just measured and it should fit in.