Where can I get a dress like the Vivienne Westwood Bridal gown featured in the And The City movie?

My debs ball (like prom) is next month and I really want a dress similar to the wedding dress in the and the City movie. It doesn't have to be that exact dress but something similar. Any ideas?? This is the dress- http://stylefrizz.com/img/vivienne-westwood-satc-wedding-dress-short.jpg