Maybe pull the blue out of the rug and go with some navy chairs and window treatments. It may be too dark for your taste, but I like dark and cozy.

I agree with using colors from the rug, but I'm not able to tell exactly what colors are in the rug. Is that a red or rust color with the blue. BTW, you have a lovely room, shape, size and natural light.

Your room looks classily elegant like this one from Suzanne Kasler. ( see photos 3-4)
http://www.veranda.com/room-decorating/design-ideas-home-renovation-south-carolina#slide-4
The colors are stunning and layered beautifully. If you place some patterned linen panels and graphic pillows it'll look great. The chairs used in this room are classic, yet have a stylish modernity to them.

The main problem seems to me to be an overuse of earth tones which can be dulling, coupled with dark wood furniture.
It's not easy to tell the wall color in the photo it looks like a dark olive brown but the lighting is probably playing tricks and maybe not doing full justice to the room
The other problem is too many lamps and side tables which are more or less the same size and style, so i think you need to do some weeding before deciding on color addition, and of course the rug will complicate that task a bit.
One can see that the tables are all nice pieces but they shouldn't all be together in the same space.
I think the coffee table needs to be replaced with something more ample.
Also, a big print or canvas, something modern maybe, placed on that empty left side wall,or a wall library displaying different colored books would give interest and animation, .
That lonesome print taken off the far corner, the dark wood furniture item too and maybe replaced with a BIIIG new lamp, something imposing.

In fact what i'd do myself would to be to empty the room of everything except the rug and the matching sofa and chair set to be able to see more clearly what should be done.
It's basically a lovely room with those windows, their cream (or white ?) drapes against those dark walls, beautiful floor but this is somewhat visually lost by too many cluttering small tables and lamps.

In other words, for me it's just as much about rethinking your furniture as adding colour, and once you have the right balance you probably won't be needing much colour addition all.

*That far window is a feature in itself and deserves to be given more value and accentuation.

lots of good advice...instead of more chairs how about a chaise longue in color...

Your entire room has a very nice neutral tone to it. You have enough pieces of furnitures. The red lounge couch is the perfect color. But if you add a piece, you gotta remove a piece to avoid crowding. You can add plants. You can add a big mirror in the empty space above the couch, that would bring in more light from all the lovely windows.

Add more red tone: pillows, thrones

Add a few more pieces of decor of copper color with some shine. Carpet is fine. The whole room has a good antique look. Becareful with new colorful carpet, it might outshine the current look of the living room.

Here are some living rooms that reminds me of your room.