xw8400 upgrade -- faster CPU -- follow-up questions

Hi SDH:

Thanks for your suggestions.  Is the following the CPU you are recommending:

http://www.ebay.com/itm/Intel-SLAEJ-Xeon-E5345-2-33GHz-8M-1333-Socket-771-Quad-Core-CPU-Processor-LGA771-/131966126330?hash=item1eb9cb48fa:g:0OwAAOSwzaJX-7ee

     Intel SLAEJ Xeon E5345 2.33GHz/8M/1333 Socket 771 Quad-Core CPU Processor LGA771

     --  $6.99 with free shipping

Regarding hearsinks, you wrote:

        3.  Hopefully you'll already have two heatsinks/fans.

See photos below -- I only seem to have one hearsink.  The other CPU spot on the motherboard does not appear to have a CPU nor a heatsink, if I'm correct about what I'm seeing.  

Would appreciate any additional suggestions you have.  E.g.  should I buy one of the "Intel-SLAEJ-Xeon-E5345," or maybe two?  If a buy a second CPU, it seems I would also need to buy a heatsink for it.  Corect?

My inclination, at the moment, and depending on your suggestions, is to buy one of those CPUs, and use my existing heatsink.

Would that work?  Would I see much performance improvement?

Again, thanks for the information.