I have the same 2009 system, but configured as a 2.26GHz 8-core.
I work in After Effects and Maya. My workstation is used primarily for motion graphics, compositing, and 3d.
Just completed a serious hardware upgrade. Upgraded the procs to 12-core 3.33GHz, threw in a GTX 690, updated system drive to RAID 0 using 2 Samsung 840 pro's, updated media drive to RAID 0 using the Sonnet Tempo SSD Pro combined with 2 Samsung 840 Pro's to get full 6Gb/s bandwidth, and bumped RAM to 32GB (1333GHz). The biggest performance upgrade I saw in my After Effects rendering tests was the GTX 690. Nearly a 20 fold increase in rendering performance from my previous GT 120. The updated procs probably sped things up another 15% or more. I'm curious how things will scale with an additional GTX 690, and even more curious how the Titan fares against the GTX 690 in After Effects.
I would first try updating to a new graphics card and see what that does for you.