Perhaps a large round table might mean a rug is not at all necessary. It could be a metal tray table, or carved wood like Rebecca Mitchell Interiors illustrates. Ideas also to consider, using multiple tables can be found at http://www.houzz.com/multiple-coffee-tables. I also agree with comments above that some color is needed on the walls. You could then hang round mirrors, or an unusual curved shape like RMI shows above.

First of all, I don't think that furniture is comfortable enough to sit and watch TV, so the TV should be remove from that room, the purple wall paper and the purple furniture is too much, you should consider another color for that wall and the furniture against the wall it doesn't look good. What is that room at the end is kind of dark and I cannot appreciate exactly what is the purpose of that room. I'm a firm believer in skylights, we have skylights in the laundry room, kitchen, living room and office, they make a big difference. (if you cannot have skylights (or tube lights) can lights are a great option. There are a lot of great ideas from everyone. I can't wait to see the after photos.

I would put the TV on the wall you have the sofa on now and use the larger wall for your sofa. Right now it looks jammed into the corner. It should be fairly easy for the "cable guy" to move your cable outlet to theother wall if you don't have one there already. Or an entertainment unit would be better for your TV set-up on that wall.

Hi Option 1 As suggested by Cornerstone above. This way the TV will be visible from dining too Option 2 Move TV to the corner of the entrance wall, next to the window, placed at 45 degree angle. The L shaped sofa can then go to the diagonally opposite corner. The wall can be a see through book shelf/crockery shelf. This is better as the visitors have some inviting empty space as soon as they walk in instead of a sofa. Option 3 TV in current position, but instead of the TV being mounted on wall, perhaps have an open shelf (like below)