Buy a Desktop Video Editing PC
Here Build a Desktop Video Editing PC
-3 price level ideas in http://www.pacifier.com/~jtsmith/ADOBE.HTM
-what PC to build http://forums.adobe.com/thread/947698
-2 how to build videos http://forums.adobe.com/thread/1104182
-another video http://forums.adobe.com/thread/1145366
-another video http://forums.adobe.com/thread/1132363
-planning & Building http://ppbm7.com/index.php/intro-part-1
-memory for LGA2011 http://forums.adobe.com/thread/1098759
-an Adobe FAQ http://forums.adobe.com/thread/878520
-several more links http://forums.adobe.com/thread/815798
-build tuning http://ppbm7.com/index.php/final-results
All things being equal, a good GPU will make a bigger difference in video rendering. However, get an I7 and not an I5 CPU. The differences, like hyperthreading for example, don't matter much for a gaming machine but are important for video editing.
Both CPU and GPU matter with the Hardware MPE. Decoding and encoding is still all CPU based. Get the I7 and a 660GTX video card would be the suggestion.