First "audiophile" system, now what? Suggestions for best "bang for the buck" upgrade?


After being beguiled with mp3s and the TV AVR, I finally realized I missed having a dedicated stereo system. With a budget of $2400, here is what I put together:
  ProJect Carbon 1 w/TizoAcrylic platter and Ortofon Red cartridge,
  Hagerman Bugle2 preamp,
  Vincent V-60 tube amp,
  Martin Logan 12 speakers.
 No special wires or cables. My room is 14x19 that is open to the kitchen. Compared to what I had been hearing, this system sounds fabulous. But now I want more fabulous. So I am writing to seek help on making short term/long term plans to upgrade. Short term means the biggest improvement in sound that costs $500 or less. The long term plan could cost maybe $2-3k or more. I have read that going from Ortofon Red to Blue might be a an inexpensive but very noticeable improvement? If speakers are my weak link, then maybe Martin Logan electrostatics would be good (when my ship comes in)?
I welcome any suggestions.
128x128etwilley
without knowing how your set up is interacting with the room it's impossible to say what you can do to make it better. Investing in upgrades without being able to qualify the results is throwing money out of the window. My suggestion would be to invest in something like DEQX...they have many levels of DSP and offer room, speaker correction. Tubes will have a noticeable impact..
Thanks for the response. The DEQX looks like a useful addition but I think my system may not be worthy as is. I know my needle is rather basic entry level, so I was thinking I would start there. Later, if I had substantial cash, I should look for a good speaker match for the Vincent. Any suggestions?
Do you have any room treatments? Anything to absorb or diffuse reflection of sound waves on the walls? 
Describe the layout, where are speakers located, listening position, carpeting or hardwood, furniture position.

The room can be thought of as an additional component to your system.