Compaq sr1900nx cpu upgrade?

hello, i am inquiring to find out if it is possible to upgrade my sr1900nx compaq presario to a dual core cpu.
nothing much, its just that the 3.2 processo, which is, but my wife plays WoW with it and doesnt reach good fps. she is running 2gb of ram which is plenty, but she lacks in cpu power. so i was just wondering if i can just find a cpu upgrade or if im stuck paying another 500 dollars for a new computer. i would just go with the new comp, however the sr1900nx is a great computer for her needs with the exception of the cpu. i wouldnt want to upgrade the whole thing just for 10-20 more fps .

any help with this would be much appreciated, thank you...