99 Contour SE's motor mount

My 99 contour' belt broke because 2 of the pulleys went bad. After the belt got replaced the car made a lound noise ( grurrr) when I stopped at the traffic light but it will be gone if I turn off my A/C. Someone told me it might be my A/C clutch is going to die. It seems like the car make noise when I put the car in reverse also. Open the hook and let my daughter put the car in drive mode the whole engine seems to lift up and down but not shaking. Does the engine mount is the problem? how about tranny mount and other mount??? How hard for me to change it myself. I dont have a whole lots of $$ to spent. Seems like $ sign every time I turn around and dont get raise as often as gas price jumps at the pump over night.
Thansk for all your hepls.

4 cylinder?

My zetec does the same thing and I've been told the motor mounts are fine.