I like Mellow's solution in his pic. Maybe he can pop back in and tell us how that worked out for him? I think you've got one massive heat sink there and it it is the path of least resistance for all of the heat. You put your hand on those bricks and they are hot. There's the proof right there. The problem is they act as poor radiators to push air out into the room. The old stove you had protruded further into the room, if only a few inches, so it probably had the exact same problem, but had the benefit of a bit more radiation into the room. The blower fans in the new stove aren't anything to write home about, but they should at least get the heat out into the rooms natural air currents.