You really are open to do anything at this point. Your pattern isn't too busy and you are neutral elsewhere. I do lean to gray, but you could either get color block (great ones on etsy and you can choose the colors) or West Elm has excellent curtains. Hang them in line with that little bit of ceiling we see in the left of the pic and to the edge of the windows. Good luck! Send pics!

I wouldn't repeat the pattern in the rug...something like this?

Belgian Flax Linen Drapery, Mist Gray, 50" X 96" · More Info

You will probably have to go custom, as that window span is quite large. How much wall space do you have to the right of the door? Are you thinking functional or stand alone panels? There are some gorgeous fabrics out there that combine all of the colors in your room with tone on tone stripes, textures, and geometrics similar to your rug. I would do euro or french pleated side panels mounted on rings and a large diameter metal rod in the finish similar to your light fixture. Alot, too, depends on your budget. I can send some photos of fabrics I would recommend and pricing if interested. Where are you located? Here is just one example: