I agree that silver leaf would be good, I have used it lots in artwork. However, it can be a very delicate operation to get total coverage in a largish area as the sheets are extremely thin and light as air when handling. There is also a product called gilt cream, which comes in different metallic 'colours'. The pewter one is great for frames, you apply it a bit like shoe polish with a soft cloth and buff afterwards. Or have a look at this link, metallic acrylic paint. you could use two shades, darker all over, let dry, then highlight/drybrush the raised detail with a lighter shade.
http://www.jandtblackman.ltd.uk/eShop/proddeta il.php?prod=LiqMetBaroque