we also have a long and narrow living/dining room. I would guestimate that ours is 8' by 25'.... an extreme rectangle.
It's hard to tell from the pictures, but overall, your layout is similar to ours. we did a lot of careful planning to create seperate living zones in the room, and balance the weight of the furniture.
Our room is very modern, and has silver grey walls, and black/dark furniture with white carpeting. the furniture running along the long walls are all low profile and very long (a 4 seat couch on one side, and a 20"x 80" bookcase/TV table on the other). the visual weight of the big black couch is balanced by a maching loveseat under the window of the short wall. the sitting area is definied by a grey graphic rug that both couches sit on. In the dining area, the glass dining table is very narrow. It can expand to be long and seat 8, but most of the time is kept small. It has 8 matching aluminum chairs that being silver, visually don't take up much weight either.
I think our room looks more square becuase the matching love seat and couch trick the eye into thinking they're similar sizes. Is it possible to replace that rocker with a matching or complementary chair/loveseat to your couch? I would also put that chair on the same rug as the couch (right now, the rug is shifted somewhat away from the rocker...). that way, the rug defines your sitting area.
not sure what the white and green? rug is doing next to the rocker (in pic #3). If it's not defining a sitting / eating area, it should likely go somewhere else in the house. On that note, if it's a suitable size for the dining table, maybe put it under there so you better define the eating area?
hope this helps....