You need a pop of color. Metallic may work. But every thing you described is so neutral. Go bold or go home.

I would buy one placemat in a silvery/greyish tone and one in a cream/golden hue, e.g.,:
http://www.bedbathandbeyond.com/store/product/wamsutta-reg-collection-chatham-placemat-and-napkins/223430?categoryId=13696

See which one looks better in the room.

I'm at a loss for what design/color table cloth to buy for my dining room. The walls are a very neutral beige.
My furniture is black (sideboard, mirror, console table). My dining room table and chairs are a lighter oak color.
These are my curtains:
http://www.wayfair.com/Sedgewick-Curtain-Panels-EH7911-0-2-X84G-EXCH1006.html
This is my rug:
http://www.target.com/p/threshold-diamond-area-rug-natural/-/A-15017211?lnk=rec|mwebpdph2|related_prods_vv|mwebpdph2|15017211|3
Please help!