I assume this is the bike and you are riding it as equipped.
http://www.vintage-trek.com/images/t...Trek89_330.jpg It is a great vintage bicycle and I am sure a pleasure to ride. Reducing the weight by 10 pounds which includes much lighter wheels will make a difference climbing. Also, integrated brake lever / shifting is wonderful and allows rapid changing of gears to select optimum climbing cadence while keeping your hands on the bars. Clipless pedals coupled with modern cycling shoes will also improve climbing performance (I am assuming you do not have cycling shoes with the metal cleats on the bottom that cleat into the pedals with toe clips and straps) and are much more comfortable for long distances.
With respect to performance, IMO it is 85% lungs and legs, 10% brain and 5% equipment. You are dealing with the 5%. So let's assume a 50% equipment performance improvement by getting a new bike would translate to an overall 2.5% improvement. It is small but small changes favor newer riders since your power production is so low.
