Your pc has a Socket 478 processor. A couple of suggestions...
Measure the fan width x width x height normally centimetres then do an eBay search for a new one.
Remove the label in centre of fan (if it has one) to reveal the bearing and drip a small drop of sewing machine oil onto it. Leave for an hour to soak through then run up.
Or if you want to put in a new heatsink as well something like this from Amazon although eBay will probably be cheaper. You will need to replace the thermal paste.