Where can I find a dress almost exactly like THIS?

I really want this dress for prom, Jennifer Hudson wore it and it looks amazing! It is my dream dress, it would awesome if someone could tell me where I can get it or a dress extremely close to this one. Thanks very much! http://images.search.yahoo.com/search/images/view?back=http%3A%2F%2Fimages.search.yahoo.com%2Fsearch%2Fimages%3Fp%3DJennifer%2BHudson%2B%26ei%3DUTF-8%26fr%3Dyfp-t-501%26x%3Dwrt&w=291&h=400&imgurl=us.movies1.yimg.com%2Fmovies.yahoo.com%2Fimages%2Fhe%2Fphoto%2Fmovie_pix%2Fsag%2Fsag_awards_2007_photos%2Fjennifer_hudson%2Fsag3.jpg&rurl=http%3A%2F%2Fmovies.yahoo.com%2Fshop%3Fd%3Dhe%26id%3D1809809198%26cf%3Dpg%26photoid%3D970424424&size=30.1kB&name=sag3.jpg&p=Jennifer+Hudson&type=jpeg&no=16&tt=2,735&oid=8e8eaf1a6a2531cc&ei=UTF-8&src=p