The harmonic balancer is the lowest pulley on the front of your engine and is held on by one bolt. It also requires a puller to get it off of the crankshaft. You may not have to pull the engine to replace it but, you'll have to make room for the puller by removing the radiator and any other components that will interfere.
It can be expensive if you have a mechanic do it but, if you have some time, you can do it yourself with regular hand tools (and a puller).
Good luck!