Bruce Chaddock

Hey, I have an older Cannondale in fantastic condition. I just put a new wheel set on it last year, it has the original Suntour Superbe Pro components and original wheel set. I don't know what I want to do with this bike. I want to start riding it to train and what not. I am in high school and don't have a steady income to support me buying a new bike. I would like to change the down tube shifters to lever...Is this a good idea? Is it an expensive process? Should I try and sell to get a new one?