I second the MacCormack if you can find it for your budget. I would also seriously consider the Adcom 5802. It is a major step up from the 545 so it could possibly address all your issues you have with your current amp.
That said, I'll echo what Frogman said as well and add the same comment as Plato with regard to room acoustics.
That said, I'll echo what Frogman said as well and add the same comment as Plato with regard to room acoustics.