I think the best colour to compliment tan is a pale chalky blue, not too bold but will look great!

If your thinking of getting black furniture I would go for a pale sky blue on the walls, if you stuck with the old furniture I would go for a yellow as yellow is known as the most complimentary colour to blue.

Well going by the colour wheel, yellow is known to be the most complimentary colour with blue and I think that would go with your sofa too.