Beth, I do not know the size off hand. But compression fittings are a no-no. They will work, but that is illegal and unsafe. You need to get a flare tool and cut out the bad section of line. Clean and flare at the ends on the car where the line remains good. But a metal line from your local parts store, and get two unions and two end connectors. That way you can install the line correctly.
If you happen to have had a line failure where it is easy to access. I would say you can do this no problem. If it is going to be difficult on your back in the driveway to bend all that line correctly, I would recommend a shop. For a referance I had all new lines made on a 91 that I had. It cost 400. That was well worth it to me.
Mike