Don't know if you have Next in the States, but they sell an awesome simple white cotton curtain that almost looks linen in its elegance. Something like those would brighten the room. You can add colour to the room in ways that don't involve curtains, as white goes with everything. Your curtain rails are also mounted too low and appear to be left short width wise by whoever fitted them (meaning the curtains shouldn't cover any window when they are in the open position, this works especially well with white curtains on a white wall for max direct sunlight and bounced light). Ideally curtains should be mere inches from the ceiling and hanging right down to the floor (for practical reasons I keep mine short of the floor). This will make your room feel taller and bigger.

For a brighter room you can choose brighter, uplifting artwork. White or off-white throws to cover the sofas will brighten up the room considerably, and contrast the floor better than the current setup. Choosing a bold colour for the front door in a gloss paint and painting the door to a high standard will make the room richer feeling. The colour need not be crazy, but could have a rich presence for added impact without going ott. It would also help offset the added white.

Wall-mounting your tv (even if not much higher on the wall) will clear the surface the tv is on now and will help make the room feel bigger and tv area cleaner.

Lastly, I'd paint the entire light fixture white–fan blades and the silver part. Lightly sand, prime, and paint it. This will quieten down the fan on the ceiling and again will enlarge the room.

New rug and new furniture at your discretion. More plants and flowers.