Agree with carrieandjimh, You will need to connect the two colors through prints on pillows, curtains, rug etc. Can you post a pic of the sofa and wall color so we can see what we're talking about here? Thx.

It's a dilemma because you know your stuck with it for years once it's on. We recently painted our cedar exterior. Started by agreeing on a general colour and then buying a series of sample pots. We finally decided on dulux colour bond dune. Amazing in itself as we rarely agree haa. It was a nice mix between beige and grey. We bought the 10 litre tin and went to work. After completing one wall I thought the paint was taking a while to dry as it wasn't getting as dark as the sample. My husband thought it was because of the lighting. I took a piece of wood and painted the sample which we loved and the paint from the 10 litre can together and yes they were a different shade. The hardware store had accidentally mixed the sample pot in double strength. It was all fixed up and we really love the result. So it was Dulux Colourbond Dune. I think it would be perfect with your roof colour.

You may use a specific light in the grey on the wall were there are two windows. While the other wall with a long slim window has a wall feature design. There are numerous features to use, with the intension that it would be on the same colour contrast. As was mentioned that the blinds would be great sprayed though in a colour that will go with the walls colour and design. Need to be a balance in the colours for both walls and the blinds. You may use one wall with wallpaper feature if you prefer. I have found a site that may assist you with the design of your choice. http://colorhunter.com/; http://www.resene.com.au/wallpaper/#

I agree but my comment means that my opinion is that colour and the way to find out would be as you say in person at a paint store but I reiterate that I have a very trained eye for colour and can only go by the sample above the rest is up to the home owner.