I like the idea of bringing some black into your room. I think lamps with black shades would look very nice and because you love pink you could get black chairs with pink cushions. You need to tie in the pink in other areas of your livingroom but I would not overdue it. It's a beautiful shade of pink but too much of it would be too overpowering in my opinion. Post some more pictures of your room if you can.

STOOL CHAIR SOFA BAR TABLE

I am looking for retail/boutique sofa cum bed in Mumbai. Can one suggest a store or designer to visit?

First, I would ask the builder to give you the dimensions of the furniture used in the plan. Since they've already done the legwork-you will know which pieces will fit. Many times folks go the the furniture store and end up with a huge sectional and it over powers the room. Second, just get what you love! You have to live there. Start to create an idea book in Houzz. You'll start to see a pattern. Then just find a sofa like the one in your pic that is in your price range. Just keep repeating until you have all your pieces. Same thing with wall decor (which I would do last). Have fun!