I would find a new mechanic if I were you.

The belts aren't hard. There are tensioning bolts like foot said on each of the accessories that the belt runs. Loosen those and the belt should slip off. Don't worry about removing that engine mount, the engine will not fall out. Put the new belts on and tension them like foot described. The hardest part about the job is the limited space that you have to work with.

I would suggest picking up a shop manual so you can do minor maintenence like this by yourself to avoid getting ripped off by mechanics.