the cart or the horse?

@ticat +1 for recognizing this and stepping up to the plate with an equally positive  reminder!

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. 

If you are dissatisfied with the sound of your system, I am betting you are using someone else's system as a reference. Let that be your guide. What have you heard in the past that you liked?