Great! It's very good to know that you've solidified your current score range by taking another test and getting the same thing.
(Quick question: you are taking the tests under full official conditions, including essays and 8-min breaks, right? It's important to do this because any deviations from official conditions might give you an advantage that you couldn't replicate on test day.)
So, CR and RC performance flipped. I'm guessing that's because you spent a lot of time on RC before the first one and CR before the second one, right? So what we need to do is make sure that you're able to peak on BOTH areas at the same time, which means concentrating on both, not just RC. Every other day, switch off.
When you say you tried looking for old tests but couldn't find them, are you talking about your own old tests? Those are located on the same page where you start to take a new test - the tests you've taken are listed lower down on the same page. You can click on the results for each one in order to view the problems again. (If you have any technical problems, call 800.576.GMAT and ask for tech support or email
techsupport@manhattangmat.com for help.)
If you also want to do some general reading (on non-GMAT things), you can try:
http://magazine.uchicago.edu/%20-%20particularly%20articles%20in%20the%20"Investigations"%20tabhttp://harvardmagazine.com/http://sciam.com/ (This can get a bit too casual for the GMAT, but it's probably worth including if you don't like the science passages much.)
You might also just want to take a look at the difficulty levels of the questions that you answered on the last two tests - that might explain part of why your peformance "flipped." If CR happened to be harder on the first test and RC on the second one, then that would account for at least part of the flip.
Anyway, basically, what you've been doing is working, so keep doing it, but you need to do CR and RC simultaneously (well, alternating days) so that you can peak on these both at the same time.