Should I change my 7.1 to a 6.1 with a rear bipole

[Hoser59]

I'm currently running a 7.1 system in a less then optimal setup living room (TV in a corner). Because of this setup my two rear speakers are directly behind one chair. (Sorry for the big picture)

Everything sounds good, but when sitting in the chair in the corner the rear channels can be distracting. When sitting on either of the couches some rear effects can be lost. I have thought of repositioning the speakers but after doing some research I think changing to a 6.1 with a bipole in the middle behind the chair parrallel to the TV might offer the best solution. Any thoughts on this? Can someone recomend a good speaker that would work with my current system? I am thinking one with mids and tweets on both sides firing towards the walls would work well. I think the other problem I'm going to run into is finding a place to buy only one speaker