Steven,
I just went on Trade-a-Plane to check on what other people are asking for a '61 172. The prices range from $29,500 to $49,500. The top end aircraft has a 180 HP engine and has received some serious avionics upgrades. Most of the rest of the aircraft are in the mid thirties, and they have times in the neighborhood of 2600 to 3600 with one at 5100 hours total time.
I thought this might help in evaluating your current aircraft.