Have you thought about changing everything up, or are you stuck with where your tv is?
Because, if you were to move teh TV onto the right wall, the front woudl be more symetrical. You could place the couch about five feet from the right wall (leaving space to walk behind it). This right wall woudl then be a perfect place to put your 7.1 in the future. Then, above where the TV curently is, you could put one surround and on the wall, in between the two hallways, you could put the other one.
That would give you a frnot spread of about 14 feet, and a viewing distance of about 15 feet (nearly perfect).
I guess the one drawback is that you'd be placing a TV in front of what is (I suspect) a very nice arched window (i.e. WAF = bad)
Anyway - you're definitely not up SH*t creek just yet. Your options are endless.
However, I'd get away from your current set-up if you can, just to align your viewing area with the TV, and have a more symetrical listening area.
