^ +1 to that.
ALL YOU NEED TO DO IS SOME DIY
You can simply get yourself a DC brushless fan (common ones that are used in computers) according to the size of the one, your PSU has. Since your PSU is old, there may not be any warranty left. Just open up the cover (not to mention when the PSU is not plugged into power - Else, you'll be modded instead of the PSU

), take out the fan, which might be fixed with the body with the help of some screws, replace it with the new fan. If you can spare a molex connector, just insert one into your PSU and just connect it with the FAN, or else you can directly connect the wires. Mostly the wires are colour coded, i.e. Red for +ve and Black for -ve, you can simply cut and join the wires and secure the connection with the help of electrical tape, and that's it. All this should not cost you more than a 100 bucks.