Laura, after mentioning room treatment, I went to the RealTraps site to get a test tone generator for myself (free). I found a few videos that go through the basics of room treatment and might help you understand your acoustic environment better.
Room Treatment With all due respect, as much as you appear to enjoy music and as much as you have invested, you can't hide from learning some acoustic theory at this point.
Before you buy that Bryston amp, review the videos and see if you notice any glaring problems with your room. You might find that some simple position changes, or cheap DIY changes can fix most of what you don't like. People with much bigger rooms find the 3808 to be a very good amp. For a small room, you don't
need more power. It won't hurt, but unless money is no object, I'd bet you Adrian's M80s that your dollars would go 5 times as far dealing with reflections in your room. (and that would also benefit your Quad setup) I have been surprised at the improvement in imaging and clarity in my room with modest changes. (Although my response graph still looks like OJ's lie detector test results!)
