Any fix for a parted rear window zipper

The zipper on my back window has come apart,looks like it skipped a couple teeth and won't stayed zipped together. I currently use the hang strips with snaps to keep the window up, but with the side windows down it flaps and make an annoying noise. I know it needs a new top, but its not in the cards right now. This is a 67 Dart GT Convertible with glass back window.