Your board won't run any dual core cpus. Heres a cheap upgrade for you: http://www.geeks.com/details.asp?invtid=CONROE865PE-BO-R&cat=MBB.
This board uses ddr ram and will run some older core2 duo cpus, but doesn't come with a backplate. You can order a backplate from asrock america for about $5. Select "cpu support" at the bottom of the page for a list of cpus you can use. This board has free shipping, but no onboard video. It is a full size atx board, so be sure your case can handle it.