6550d is a very weak gpu. It's worse than the 6670, which can't even handle bf3 at 30 fps on your resolution.
If I were you, I would build a pc, you would get a better deal out of it, along with having a great experience along with it.
If you can't, then just go with nbelote computer.http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=4990219&CatId=2627
destroys the other one price performance wise.