Cord repair is fairly easy, although somewhat tedious. You carefully pry the trim off, open the sash well, and thread in new cord over the pulleys and onto the weights. DH and I did about 10 of the 17 windows in our house when we moved in 5 years ago. We found detailed instructions online, and sash cord can be purchased about just about any hardware store. The hardest part was getting painted trim off without destroying anything.
We're working on the fireplace upgrade (wood-burning insert) now. We've had the furnace flue lined by a chimney company that we found through http://www.csia.org/. We liked them, and will have them back to do the fireplace flue. Be wary of any company that doesn't go on the roof as part of the estimating process. We had a company try to bid based on BTUs of our boiler onlyThey never looked at the damage inside the chimney or at the first course of bricks. The company we hired noted all of these things and took B&A photos to prove it.
Good luck!