CPU or Graphics Card Upgrade for Video Rendering?

I do a lot of animations in SW 2011 and wanted to know if anyone could advise me on whether to upgrade to a machine with a faster CPU or Dual CPUs or go with Dual Quadros in order to get through the animations faster.

My models are typically very simple - less than 20 models in any given animation.  I am currently running a T3500 with 12 MB and a Quadro 4000.  Some of the animations will take 100 hours to complete - and I am not using high quality or high AA settings.  The ram usage never tops 4GB at any time, so I am certain that the ram is not the bottle neck.  My thought is that the CPU is the bottle neck and I could add a second Xenon to this work station if that would help.

Please post any advice or questions.  Thanks!

SolidworksAdministration