Without seeing it nor the colour on your walls (which also plays a part), I would say you could take any one of the colours from your carpet as your colour for the upholstery. Yes you can choose two complementary colours for your upholstery but make sure they work tonally. (To do this take a picture of the colours and render them black and white; the colours for your upholstery - even if they are different - should have the same level of grey in the b&w photo).

Photos would be helpful.

First, I think rearranging your furniture and getting the furniture off the walls and float them in the living space would look nice. I'd nail down the arrangement before selecting new rugs. Where the chandelier is, try floating your sitting area (with the coffee table) below the chandelier and angle the current area rug. It's okay (and looks quite cozy and open) to have furniture floating and be able to wall around the furniture. You could have another seating area where the arrangement is now. Oh...yes, your mustard walls can work as is. Let's start with the layout first. :)

Hi Raghvendra! What I understand is that you require ideas for cushions and also for the wall. First of all, decide on the theme which you are going for.....modern...European....etc. Your furniture looks a mix of the two. As such a full view of the room would help one to decide on the best combination. Also the furniture material esp sofa will decide the texture of the walls and the cloth you will use for cushions. Also the size of cushion will matter. Personal choice of the color is best. I always go for rustic looks which matches most & mingles with all set ups. It give a look of luxury too. Pl consider all these facts before you decide. Hope this will help you. Looking forward for a happy home!!