I agree with Beverly, no table runner and swap out the curtains (though I wouldn't go for that color she suggested).

If your looking for an accent color though you have a pretty neutral palette so anything would work. A red, navy or burnt orange would look good with all that gray.

You need some art and window treatments before you decide on the table runner.

I'm not a fan of table runners.

I like Beverly's suggestion about new curtains (though not the "puddling" curtains) and raising the curtain rod.