No clue, depends on how much they want to rape you for, tbh.

Its pretty hard to fuck up putting in a new fan. I know it can be intimidating to do work on a PC if you dont have alot of experience, but installing new fans really has little to do with the actual main parts of the PC. You could have that fan completely stop working and 9 times out of 10 you wouldnt even know.

Id open the case and take a look inside, find the fan, and trace the power cord it uses to where it plugs in at. Unplug it, unscrew the fan from the case, screw in the new one, and plug the power cable back in. Total it should be about 5 minutes worth of work, max.

If you have any questions about it let me know, and Ill see if I cant find the schematics for your computer and show you exactly what I am talking about with pictures. =)