We shouldn't call someone's system or components junk; many of us have financial or spousal constraints......and can have really fun and enjoyable systems without dropping $100,000 or more.
However I do agree that the OPs speakers are not the limiting factor, and that maybe the amp upgrade he's looking at may not bring the sonic upgrade he is looking for.
I'd dump the Monster HTS, and you didn't mention how your power looks (other than the HTS). If you have not done so I'd look at pulling 2 dedicated circuits if it's feasible (about $500, but use good cable) and 2 high quality receptacles like Furutech GTX-D(G Gold) or GTX-D(R Rhodium), or Oyaide R1. Plug your amp directly into the receptacle, and you can connect the signal components into a nice audio quality power strip/surge protector. The power upgrade will pay large dividends weather you keep your current amp, or decide to upgrade it.