Did you buy that car as is, or is there a warranty?
Get a friend who definitely knows how to drive stick (as a comparison - not a flame) and see if he has the same problem. If so, you may be experiencing the common "MTX-75 synchro death". Do this ASAP and get back to where you bought the car to get it fixed (on their dime). Otherwise, find a good tranny shop.
The shifter should not cause gears to grind.
EDIT: Or, on the other hand, do whatever Terry says. He is THE expert.
