First off, if you are wanting help in valuating your old bike for a possible sale, go to Classic & Vintage Appraisals. Read through some of the other threads and you'll get an idea of what kind of info to provide to get the most feedback.
As to the fit... it is truly a poor fit, you will probably want to sell it and replace it. Then again, you might just need to 'tweak' it a bit to improve your comfort- stem swap, different width handlebars, slide the saddle fore or aft. Just depends on how poorly the bike fits to begin with.
If you do find yourself in the market, identify what type of riding you will mostly be doing and research/post in the appropriate forum or you could just play it safe and post in the General Cycling forum.