Suggestions for Modifying/Upgrading my system

I'd build around your McCormack / Klipsch because in my opinion the advancements LP playback have by far exceeded those of your current back end. 

Any used Well Tempered turntable would offer great stability economically and the best Benz Micro cartridge your budget would allow because of their balanced presentation and their attractive upgrade program.

If your media is mainly digital I'm ignorant and still unimpressed so I wouldn't spend a dime on it, but that's me.

Good luck with it.
 

I would try to visit as many dealers as I could and audition speakers.
Like, m-db said, I think you could do better speaker wise.
I own a pair of DNA-1 monoblocks-just upgraded by SMcAudio, as well as a RLD-1. They worked very well with Vandersteen speakers.
Though I disagree with m-db, regarding digital streaming. Using 
Spotify has made me give up my CD collection. (I grew up with turntables and vinyl and can't see why I should go back). I would suggest getting a Bluesound Node. The internal dac is pretty good, and you can always upgrade later- much better than the tablet you currently use.
Bob

The Klipsch Forte III speakers are truly a new, good sounding speaker. Different than what one stereotypically thinks of Klipsch or a horn speaker.
I'm not saying there aren't speakers out there that will sound better but there is a heck of a lot of bang for the buck going on.