Yea the chip will work but...
Last night I was searching for more information on the motherboard inside your computer and although I saw the words AM2 I also saw the words Socket 939! If it's a Socket 939 then the CPU you linked won't work and you'll have to search the second-hand market for an upgrade.
I'll search around a bit more later, just woke up
, and report back to ya.
The CPU you linked is fine. Infact i've seen people upgrading to the 125W 6400+! You might need to update the motherboard BIOS first. So do this before exchanging the CPU.
What OS are you running?