Andi gave you GREAT information!
Here's a few more hints:
Check with your LAer to make sure the batting you want to use is one that she is willing to use. I've had 2 battings that have been brought in that I really don't want to use again. They were inconsistent in their thicknesses, which gave me inconsistent tension.
Don't be surprised if your quilt top will be gone for several months. It depends a lot on how your LAer handles her backlog. Some won't put a quilt into the queue until it's in her hands. Some (I'm included) don't want more than a couple of month's backlog in the studio and have an ongoing list for the months further out.
If your quilter doesn't ask, make sure you let her know your budget for the quilting on this quilt. That way neither of you are surprised when the bill is given.