One other thing: If you decide to replace the timing belt, consider replacing the water pump as well. Most of what you have to remove and work through to get to the timing belt is what you have to get through to replace the water pump.
With a high mileage vehicle, it's probably a good idea to do both the belt and the pump, particularly if you have a mechanic do it. I just had the belt replaced on my 97 Mystique 2.0 and at the mechanic's suggestion had him replace the water pump as well. Labor total was over $300 but only $50 was for the water pump, since all the "get at the pump" labor was already done.