Slightly off topic... You might be better served putting the money into something more modern. Sometimes the older cpu's cost as much or more than the new ones because of the supply issues.
I just pieced together a new computer for my mother, complete with everything except mouse and monitor for 200.00 usd. This is low end by today's standards, but will be faster than a socket 939 system with an fx60.
ANY socket 939 CPU that you buy will be a complete waste of money, especially for gaming. This is because you'll be stuck with an AGP slot that would require you to spend more on a Radeon 4670 than a Radeon 4870! Ditch the board, CPU and RAM in favour of an Athlon II X3, a Radeon 4870 and 2GB of DDR2 or 3 (depending on which board you get).
I agree with full upgrade, however socket 939 definitely was NOT limited to AGP. I have an A8N-SLI Deluxe and FX-60. Note the 'SLI' in the name - can't do SLI on AGP. And on a side note, I still use the FX-60 and A8N from time to time and currently use a 4850 in that computer. Not a bad system really.