I hope your not planning on getting her 6 surprise dresses, one's enough!
Unless your getting it ready made from some shop, your gonna need to get a designer who can pick out the kapra for the dress, do kaam, and soo on! There are many notable people on gupshup, who do this, and do it very well!
Go to the classified section
Classified Ads , and find threads by cyma345, prototype, stoppit, and sairaji. They have done many orders here. If you want I can give you other websites, but I'm not sure how trust worthy ther are.