WAIT! Let's not spend all your money yet. You've got a small room, near field. People like your speakers. Your components are not anywhere near top end but for the most part they are a reasonable match (preamp seems weakest but it's not an AVR as one poster said).
Try a mid-priced, smallish REL subwoofer. You can get them used for $300-$500. They add dynamics and some punch for sure, but RELs are voiced to add a lot of the life you are looking for. Even if that doesn't totally fix your itch, you should have a sub as an option in troubleshooting the room dynamics anyway.
Amazingly, RELs actually seem to help the entire spectrum bloom. I'm not a dealer...I just own 5.