Your current CPU is socket AM3, the new one you're looking at is Socket FM2, they aren't compatible with each other.
You could try looking for a Phenom 2 x6 1035T/1045T on ebay or second hand somewhere.
Conversely, gunning for a Phenom 2 x4 is your best bet, more cache, faster, can overclock/under volt like champs.
Something like this off ebay: http://www.ebay.co.uk/itm/AMD-Phenom-II-X4-945-3-GHz-Quad-Core-HDX945WFK4DGI-Processor-w-Grease-/221308268840?pt=CPUs&hash=item3387003128
Have you also tried unlocking the cores on your current Athlon?
--::{PC Gaming Master Race}::--