Yea it's kind of a bummer, but that's what you get for being in the middle of the building. Plus, with a mostly square room (the rear wall is at like an 18*), the less reflective surfaces the better.
If I had a random grand to throw around, I'd totally buy another set of these monitors for my house. The sub adds so much that is missing from just 2 monitors, especially when you can isolate it with the SubDude (see below).
So far we're just using a couple Auralex roominator kits, Auralex MoPads, and a SubDude (best investment ever). Opted out of diffusers and bass traps for now but at the same time this room will be mainly used for editing and other post-production shit rather than serious mixing.