Your Omega speakers are just fine and the Zamp is a fantastic little amp...I own both. If I were in your shoes the first thing I'd get is a subwoofer. A SVS SB-2000 Pro would be a great starting point to look. It will change the complete complexion of your system. No matter what you end up with, I think you'll benefit most from a sub!!!
Second thing I'd do is connect your Node 2i directly to the amp and see how it sounds. The Node can act as a preamp...even connecting a sub.
If you're going in the right direction and want to continue (and you should), consider a Zpre which matches the Zamp. Another great option is a Schitt Saga+. They are both surprisingly good and you'd be hard pressed to hear a different between the two.
To finish things off you could then upgrade your DAC and just use the Node as a streamer. Lots of fantastic low priced options out there.
At this point you'd have a great sounding budget system and plenty of money left over for truly finishing touches like quality, but reasonably priced, cables and outboard power supplies.
Best of luck....Tim