85 celsius would be 185 degrees fahrenheit. If you haven't already.. I'd take the side cover off of your tower to give it some air. I'd also keep your pc off until you're able to buy a new fan.
First and easiest thing to do would be to reapply the heatsink ... Detach the heatsink, sand it down, apply a thin film of thermal paste, and reapply the heatsink to the CPU ...
That costs practically nothing and may solve your problems ...