Calling All Vintage Styling Experts: Help Me Accessorize My Outfit!

I've got a dilemma. It's my sister's wedding next month, and it's being held at a city hotel. I have the dress (Warehouse silk dress with lace overlay, I thought it was quite 30's or 50's, £1 from a car boot sale!), and I now have the shoes (champagne satin slingbacks, BHS, £25).

But how do I finish the outfit off to make it look interesting and vintage?

A full hat isn't necessary as it's not a church wedding and it's my sister's second marriage, but I wouldn't mind some kind of headpiece or a simple flower. Also, what colour lips and nails?
What kind of handbag/purse? Should I wear jewellery?

Any suggestions would be greatly received!