If you don't plan on doing any demanding gaming on it $250 is way more than you need to spend. I run my HTPC with a 7770 I picked up for $95 (when it was fairly current).
But, for $250 IMO these would be your best options currently: http://pcpartpicker.com/parts/video-card/#c=152,146&sort=a8&X=0,25072
You can watch that site and find deals all the time. I have seen 290x ~$250