I'd get them rear speakers off the end tables and on the walls, up towards the ceiling and away from the couch. They could actually be mounted on the side walls opposite the couch. I think in these positions(especially the side walls), bipoles/dipoles might work nicely tho I've never used them myself so I can't say from experience. When surround sound 1st came out, the optimal position for rear speakers were high up on the rear wall close to the ceiling of normal height. With my old HR setup, I had bookshelves mounted this way and the surround sound was stellar. I now have identical floorstanders, front & rear and now have the rears hugging the rear wall corners.
I also fully agree with Brian in that moving that couch out into the room would make a huge improvement so it's ashame it's not an option.
Cheers,
Robin