When I made my Chun-Li costume, I altered Simplicity's cheong-sam pattern. I'm sorry I don't have the number at the moment, but it's in the Evening Wear section of their book.
You'll also need a pattern for the puffy sleeves. I think I altered a wedding dress pattern for them - they have GREAT puffy sleeves!
Oh! And if you want the extreme curves that she has, make her belt from a waist cincher pattern - it works brilliantly!
I hope I've been able to help... even just a little bit. Good luck with it!