If you've had the pre-reqs within the past year or so, have a decent diagnostic VR score, and have the focus to really immerse yourself in MCAT study/practice, I think you can do it. If I were you I'd take the free CBT 3 test and see where you stand. This is key.
Since I had had the pre-reqs all within the last year, my diagnostic wasn't terrible: 26. I took that about 5 months before I actually ended up taking the MCAT because I procrastinated and kept putting it off. I didn't really start studying until about 5 weeks prior to the June 15th MCAT. And to be honest, I didn't study that much the last two weeks before the MCAT (mainly took practice tests). So it was really closer to a month of study. And while I have no idea how I did yet, my last four practice tests were 30, 30, 31 and 32, on a definite upward trend.
I suggest that you need a decent VR score to begin with, because that seems to be the hardest section to bring up without a lot of practice. Definitely get EK's VR book and 101 Passages if you find you do need practice. After reading their strategy my VR easily jumped from a 9 to an 11 and generally stayed around 11. PS was my nemesis. I wasn't able to break an 8 until my last four practice tests on which I finally got 10s (but on the real thing I'm betting I got an 8 or 9). You'll need to do a ton of practice problems if PS isn't your strength. And after my 8 diagnostic in BS, I was scoring 10 and 11 in BS after just a quick review of the EK bio book. However, the later CBTs had a lot more orgo in them, so I found my BS score suddenly dropping to a 9 on the more recent tests. After I finally brought myself to review orgo I was able to pull my BS score back up to an 11. The best bio review I found was EK's 1001 Bio questions. All passages, and excellent practice.
I don't have my score back yet, but I definitely think you can do it if you've got the background you need. If, however, you haven't had the basic science courses in a few years, or your VR diagnostic is a 6 or below, it might be tough to hit a 30+ is only a few weeks. You'll also need some serious dedication to MCAT studying (6-8 hours a day). Good luck!