It is only twice as expensive and 12 times slower than a nVidia GTX 650 Ti Boost.
So: No, it will not run very well, it will work, but so does a $ 30 card. And it is very slow because it does not support hardware acceleration.
Translation of Harm-speak: Premiere CS5.5 can only take advantage of GPU acceleration using certain Nvidia-based cards - there is no advantage with ATI cards. So the GTX 650 Ti Boost or 660Ti would be much better choices. You may need to do a ".txt file hack" to tell Premiere to use the Nvidia card if not on Adobe's default list.
Safe Harbor Computers