Have problem need help please

Today when i started my car (94 with a 3.8) it shimmed and shuck and the idle speed was really erratic even after i put it in gear. as soon as i gave it gas though i seemed to run just fine untill i had to stop for mare than a few seconds. I feels almost like both motor mounts a bad (and the amount of movement that is visable when looking at the engine would suggest at least one is bad, i can also pull on the engine when its cool, and it will move about 2-3 inches to each side), but that would explain the erratic idle speed would it? Could it be a head gasket?(please God i hope not) or maybe a combo of a bad mount and a leak in the vacuum system? Ohh i did a tune-up(cap, rotar, plugs, wires, air and fuel filters) about a week ago. How do i change a motor mount of one of these cars? Someone told me i had to pull the tranny on the automatics, if so i think i just might shoot the car(just kidding, ill take it out on a moto-cross track first but that too would take more than a motor mount being bad)I like this car and i have put a lot into it already but its really begining to piss me off. I've never owen a ford before, ive always had chevy's and i know them pretty well. Are all older fords this much head ache? Does anyone have any advise about what the problem might be?
Thanks,
Jess