You have great pieces to work with... don't think you need new furniture. I think part of the problem is furniture placement. It's hard to say without a floor plan, but I would consider moving the couch to the wall that has the 2 chairs and put the two chairs on an angle on either side of the fireplace. I'd place the sofa away from the wall with a sofa table behind it to add some depth. The lamps can go on the sofa table. An patterned area rug with the colours of your cushions would pull the room together. I think you also need a coffee table. One option might be to see how your end tables sitting side by side might look as a coffee table... or you can use them elsewhere? I'd also go to a deeper paint colour. Right now, your floors walls and soft furniture are all of the same saturation. If you went a bit darker on the walls, it would make your furniture stand out. I'm thinking of mossy green.