First, congrats on your great strides. 20+/- points is a really strong accomplishment. That means you can do much better.
Take some time and really study the test when you aren't doing anything else. I suspect that your brain was overloaded.
If you can take another four months and really concentrate on the exam, you should be aboe to get into the high 160's or even the lower 170's. I don't believe anyone has a "ceiling", but you will only get out of the test what they put into it. You must address their weaknesses by tailoring their study program directly towards those weaknesses.
If you are a slow reader, concentrate on improving your ability to read dense material but with great comprehension. Read the Wall Street Journal or Scientific American regularly, and stop reasong SI and the local newspaper. Read Shakespear's plays and other dense material. It's going to take some time, but you will see improvement in your speed and comprehension if you practice regularly.
Practice LG every day when you get free time. If you are waiting for a doctor's appointment, pull out your logic games and practice them. Practice the LSAT at the mall or other noise-filled locations.
Practice LR questions by type...and do them over and over and over again until there's no trick they can throw at you.
You can do this...good luck!