Rusted Frame

First i want to say that i am not all that smart with cars and do NOT fix them myself. Now saying that i do have a 1967 Dodge dart 4 door sedan that i have been driving and still do. So i put it up for sale as i have hard time driving it due to surgery. So i took it in to a shop and now they are saying that the Frame was rusted from front to back. One person said it was a 60hr wielding job. So Can the frame be replace? Can it be repaired?? Also was told this is a unibody?? does that mean you can not take the body off the frame?? What are my options or is it not worth fixing?? ANY HELP would be Greatly Appreciated....