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
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.
My room is rectangular 14 x 19 with one short end open to a large kitchen. The speakers are near the corners of the far/small end, out from the walls. The room is carpeted with drapes and leather furniture. Speaker placement/sound seems very good, sound carries well, the length of extended space and sounds rich in the 'golden triangle', nice range and imaging. But it is a "family" room not a dedicated music space. At the moment, kids and wife are tolerating the intrusion but I don't think I can change the layout much. I was thinking since this is my first real system that others more knowledgeable than myself would look at what I have and say.."well the first thing you need to do is....
First, Welcome Etwilley. 
Second, maybe you could post some pics of your 'sound room' on Agon.
That would help us determine if you need some change in placement or adding sound treatments.
Since you now enjoy the sound you have, you probably have things placed well, but a small change sometimes makes a big difference. 
I can sympathize with your need to accommodate the rest of the family- My system is a 'best compromise' for sound vs. living space.
Your system looks good. So, could you tell us, what do you feel is lacking? Have you listened to other hifi systems?
HTH Bob 
Nice to have you on board the good ship Audiophile! 

Your solution is contained in your post. You seem to dismiss cables as efficacious elements of a high end rig. I have had the pleasure of changing the opinions of industry members (read manufacturers - well known ones) and 4 or 5 engineers who mocked cables, but now pursue aftermarket cables for their purposes. 

I suggest you put your $500 to work on procuring a set/loom of cables for the rig. It will collectively be as important sonically as the addition of a new component. It is one of the easiest and most effective steps a person can make to obtain better sound. 

If you disagree, I'm not interested in debating the subject.  :)