There are numerous sellers here. The trouble may be getting it in such short notice. Try Sherry,
Custom created by YOU Boy & Girl dog clothes by SherrysPetStuff. Cathy,
Washable and reusable dog and puppy pee pads, belly bands, and diapers by T. Bumpkins & Co. is great too but she has had some recent issues with her pup so the time limit may not work for her. Connie is wonderful to work with too,
http://conniedressmydog.com/. There are many others on here too! Hopefully one of these can make it for you.
Wish we lived closer. Me and my girls would have loved to come to the party!