This was the shelf.
I cut a cute sheet into strips. I wanted it to go around the shelf two times before it was gathered. I gathered it, and then serged the edge. You could just zig zag the edge. Then I hot glued the whole thing to the shelf.
Then I made a blanket sandwich, just as if I was making a quilt. I used two layers of batting, and two layers of the sheet right sides together cut the same size as the shelf. I sewed around leaving an opening and then turned it. I ended up hot gluing this to the top of the shelf.
I added a pillow and blanket an Ta-dah! I have to say it is the cutest shelf around. This American Girl bed cost me $1.50 because I had just about everything. This is probably more information than most would want but on the off chance that some mom finds herself in the same position I thought I would share.