I used a small piece of scrap for the whole thing that I bought at walmart for cheap months ago. I lined the front parts of it with fusible fleece to add support in case she still wants to sit in it. :) I cut the old one apart and traced it onto the new fabric and went from there. I hated how the bottom of the seat would always come off and she would bring it to me multiple times a day to put it back on for her, so.... I added ties to keep it on this time.
It's not the best sewing job i've ever done, but it works. I used what I had on hand and hurried up with it. I'm not concerned with tiny cosmetics on this one.