David`s Bridal Gown Style 5339

I have a size 10 of this dress and it doesn`t fit. Do you know where I can get a size 12 or 14? Help. I love this dress and it is very elegant, but the one I bought on Ebay is to small. The style # is 5339 and it`s called the Michalengelo. I am willing to do a trade or ? The one I have was used once and has been professionally cleaned and put back in a viewing box and also has the outside box as well.
Thank you!
Debra :)