My room is somewhat similar (13x14) and have got 11 GIK 244s (some with the wood things on the front - I forget what they're called) and other just bass traps. Two stacked in each front corner, three along the front wall in the middle, two at the 1st/2nd reflection points and two on the ceiling. And since my head is pretty close to the back wall, I took a few unused down comforters and folded them into a box to place behind my head.
I have quite a good selection of speakers and the treatment seems to work pretty well with just about all of them.
Like others have suggested, I'd just contact GIK and send them a photo of your room and they will make suggestions as to which of their products will more than likely work well for your listening room. I bought my treatments a few years back and the prices were reasonable. The shipping sucked, however.