I don't know your skill level, but if you aren't up to fixing it, I suggest changing mechanics before changing components. A decent mechanic should be able to diagnose and/or repair the problem, or at the very least identify the cause and suggest a course of repair.

If you want to work on this yourself, you'll need a repair stand, or at least a way to keep the rear wheel off the floor. Possibly you can throw a pair of ropes over a rafter in your garage or rafter and hang the bike so you can work on it.

Start by trying to shift by either direct pressure on the FD arm (where the cable is attached), or by pulling the bare FD cable's inner wire away from the frame at the down tube. If it won't shift crisply, try backing off the outer limit screw and see if that helps. If you can get it to shift with manual overide, then you know it isn't the FD, chain, or chainrings. Now it's only a question of getting the lever and cable working properly, either using the cable adjuster if your bike has one, or resetting the cable (probably tighter) using the pinch bolt.

There are a number of good tutorials on FD adjustment available on the net. Search under Front Derailleur adjustment, and review a few untli you have a sense of how it's done.