Here are my thoughts. Finish the applique work first. I would make sure the backing is slighty larger than the top so you can trim and square it up after machine quilting. Spray basting works well enough so you shouldn't have to sew/baste it also.
Binding isn't as hard as you might think. Here's a lesson on binding, if you have time. Good luck!
http://www.youtube.com/watch?v=Ot7Trk6J2Vw