It doesn't matter if it is the V6, or the I4 motor. In both cases it is an easy fix. The cheapest way to fix it has been mentioned earlier, that is, go to the junkyard and purchase one off a wreck. I bought one for $60, including core charge about a year ago for my 280,000 km Chev Beretta.
Buying a Bosch from Canadian Tire will set you back about $200.
1. Unplug the battery using an 8mm wrench. If you have an anti theft radio, you may have to get the new code from the dealer to reset it so it will operate again.
2. Loosen the serpentine belt. Use an 18 mm wrench or a 3/8 drive johnson bar if you can get it in there to increase the tension on the idler pulley so that you can release tension on the belt.
2. Disconnect all wiring to the alternator. There is usually one plug, and one live feed bolted on the rear of the alternator with a 10mm bolt.
3. Disconnect the bolts holding the alternator on. Typically held on with a combination of 10mm 13mm and 15mm bolts.
4. Remove and replace alternator and reverse steps 1 through 3.
It is an easy job that can be done in your driveway with basic metric tools. No need to see a mechanic if you are slightly handy.
If you decide you would rather someone else do it, an honest mechanic labour should only be charging for .5 hours.