If you could take a picture of the bike and post it, that would be helpful. It's hard to say whether you received good or bad advice at the bike shop. First they base their fees on all new equipment. Second, some of them don't like to work on older bikes so they jack up the repair bill then hit you with, "You'd be better off with a new bike". Which they would be happy to sell you. And some like to repair old bikes and give honest repair/replacement prices and sometimes use older/used parts to lower the costs.
It's hard for us to evaluate based on the limited information you provided and no pic.