i would do a simple beige curtain with a gray and yellow pattern. also the room decor is not really mid century, so i would just get chairs with wood legs to tie things up.

On my monitor the sofa and rug do not go together. Sofa looks to be blue and rug gray. I wouldn't get the curtain you chose I would stay with white linen. Chairs should have a skirt you don't want all the furniture up on legs. I would get a stripe fabric on the chairs. Hang the curtain rod closer to ceiling and make sure the curtains just touch the floor not pool on it.

I agree IMO that rug doesn't work with your sofa. I would select drapery panels in a color other than white.