2000 Plymouth Voyager Water Pump

I recently went to a mechanic because my van was leaking coolant from the passenger side area of the engine. They told me that I need a new water pump installed and to install a new timing belt and timeing belt kit. 3 years ago (30,000 miles ago)I had a timing belt tensioner and a new timing belt installed but opted not to change the water pump cause there was nothing wrong with it at the time. My question is, since the timing belt is only 3 years 30,000 miles old, does the timing belt really need to be replaced being they last up to 100,000 miles. I would like to only replace the water pump since funds are tight.