Good fabric choice for my dress straps?

I've got my eye on this awesome dress, the only problem is that it is a strapless. I'm thinking about just altering it a little so I can have halter top straps. Now my question is, what is the best fabric to do this with? I plan on hand sewing, as I don't trust my sewing machine. I don't want a stretchy fabric, as I have rather large breasts, and I don't really want to stretch out the fabric. The dress is a baby pink with a silver, almost-black lace overlay. It is a short dress and it has tiers of the lace and sequins on the some of the tiers. Any ideas? Thanks in advance! :)