It looks like your link is missing, but I assume you're talking about this girl
? I'd probably make a two layer craft foam structure (one layer for the base shape, and one for the raised designs) and seal it with white glue. From there you can paint it with acrylic paint or with gold leaf. You might need to strengthen it with cheesecloth backing - I've also used posterboard for strength and it's work just fine.
If you haven't worked with craft foam before, check out the craft foam armor tutorial
! There's also lots of information in the Props and Accessories Forum.