You've got a great start! First, I would create an idea book in Houzz. Find an inspiration piece, artwork, area rug, pillow. When I saw the gold on your fireplace. Light bulbs went off for me because gold is so in right now. So I did a little mock up-it might trigger some thoughts for you. I would consider moving the loveseat in front of the window to the other side so it's not "blocking" the window. Would rather see chairs there-won't feel so closed in. Go with a square rug. I'd stay in the gray tones for chairs. I think anything darker is going to suck up all the light. If they can go on the window side, I would not do a high back. Keep them about the height of your loveseat.

I would recommend that you not get wing chairs because the backs are too tall to float in the room and will create a visual barrier. Seriously, I think you would be best served to get an interior decorator involved. They will be able to source the items you need and bring this lovely room up to its full potential.

Agree an interior decorator can save you time and money, but if that's not an option I think you need to get the rug next. It will help with the colors to choose for chairs, window treatments and accessories

Hmmm. I thought my first post failed so I tried it again. I don't know how to combine them...