I feel bad that you haven't gotten any replies yet. I am not familiar with the sound of your gear (except for the speakers), so I can't directly answer your question. I did note that you failed to mention cabling. Without starting a flame war, cables, IME, do indeed make a substantial difference in a system's performance, particularly in stereo. Think about upgrades staring with ICs, then speaker cables, then power cables.
Other than that, what is it about the sound you now have that you feel could be better? Answer this and perhaps you'll get more replies.
Other than that, what is it about the sound you now have that you feel could be better? Answer this and perhaps you'll get more replies.