Newbie question-- where to throw my frogskins next?


Hey folks, my first post--

So my new year resolution was to get into vinyl and these past 11 months I've been on an very enjoyable, and thanks to craigslist fairly affordable, audiophile neophyte journey.  I really barely know what I'm doing, but think I've lucked onto a pretty sweet vinyl setup;

AudioTechnica 120 turntable (with their standard cart)
Marantz sr7007 (using pre-outs for front speakers, but built in for surround speakers)
Moscode 300 ($150 craigslist score!)
Klipsch Forte I (replaced crossovers and tweeter diaphragms) 

So my question is, if I wanted to throw about $1000 at this system, where would I actually hear the biggest difference?  Better turntable?  Tube preamp?  Save my money as the difference would be negligible?  

I'd love to find a deal on a Mcintosh preamp, but the truth is I use the system for home theater and gaming and appreciate all the HDMI switching and surround sound the Marantz is giving me.  But I am also listening to vinyl every day now...  :-)

Thanks in advance for any advice!
128x128argonsteele
Just Curious what tubes are in the Moscode.  There should be 4, total??? They may be good ones ,or if it was tube raped (or they were dead), some new cheap stuff.  New tubes are good because it will work correctly, not be noisy etc.  Old is good,- if tubes are working and also in good condition.  Older tubes sound better than new production tubes. in many instances and are more valuable.  Contact me and I will tell you what you got- if you want.  No I will not buy etc, just advise.
The Phono Preamp choices are numerous.  I don't know what you want to spend, (About $400) but the Graham Slee 2SE is very very good, I love mine. Did anyone tell you this can be an expensive hobby.
Congrats on your purchases. I believe you have optimized what you can get out of your TT and did not exhaust your budget. Just curious, were the cartridge and cork mat purchases based on recommendations made in reviews of your turntable? I am not familiar with the AT 120 EB. The thoughts presented in my previous post were made based on your budget and the fact you were trying to incorporate vinyl into an existing system. I was trying to encourage you to spend slowly and wisely. This I think you have done.

As you go done the road to upgrade I have to say that I agree with paraneer regarding the 'weak link' concept and the AVR preamp being such link. Your are now in a position to consider the approach offered by him, which given you have a 2 channel amp and a phonostage, will allow you to search out a quality used line level preamp with HT bypass and 'have your cake and eat it too', a 2 channel audio system and a surround sound system.  
OK, learning about HT bypass today.  :-)  Yes, the cart upgrade was recommended by multiple reviews on the turntable and seemed a no-brainer for $100, same with the $15 cork mat.  

In the meantime, I disconnected the Moscode amp and took off the cage to examine the tubes. The two outer tubes which are marked GFQ7 on the board are Westinghouse 6CG7/6FQ7 tubes. The inner tubes, marked 6DJ8 on the board are 6DJ8-ECC8 "made in USSR" tubes.  Any opinions on those?  :-p
Please let us know what you think once the phonostage and cartridge have been in play for a while. I think I might check into the AT 120 myself. Looking for an inexpensive cartridge.