I have the same fireplace and the same rug! we have the walls painted white with white accents accessories and it definitely makes the room bright. I will try to post a picture.

You probably could have gone with the lighter shade than the one you chose, but it is fine. I cannot see a closeup of the curtains, but they look okay. I'd hang them on rings, so they'd hang better. I assume that you are putting curtains on the other windows. You need yellow pillows on your couch.

White or off-white curtain panels hung wider than the window (so that they only cover walls when open) would create a nice contrast and brighten the space. Also, artwork with white background or big white mats (and perhaps black or silver frames) would also look nice. Good-sized art would break up the wall color and could look stunning!

Instead of painting, I'd consider better lighting. Recessed lighting doesn't necessarily warm up or brighten the room. Consider table lamps and floor lamps so the light shines closer to the people in the room.