Here is the sweater before I cut it up.
I cut off the sleeves.
Using another dress as a reference, I cut the remaining pieces - not shown in this picture is the bottom part of the dress - sorry!
I sewed a brown ribbon around the dress. I sewed a couple little pleats on the front and added a zipper to the back so the neck could be like a turtle neck. Here is the finished product. Now she just needs a headband to match :)