That dress is cute! I would say something metallic, but in a very subtle color. Maybe something a light gold/yellow or even a pastel purple would set off the flowers on the dress nicely.
If you're not a fan of satin, you could opt for something strappy, or maybe even espadrilles (sp?)!

Let me find some examples..


(you're probably not looking for manolo's, but its just an example LOL)





Just a few suggestions. =) Hope you find what you're looking for!