I'm glad you're asking the question, because you do want to make sure that you're prepared to get the most out of your class. It might not be as bad as you think, though. :)
Messing up the timing on the test can result in a pretty big score drop - that is, it looks like you know less than you do. If that's part of what's going on, then your level may be just fine for class (though you will have to work on the timing, of course).
I'm going to guess that you tried the FoM diagnostic and that's why you worked on FoM for a week? If not, you can try the diagnostic now to see how you do (this can be found in your student center).
Next, you can use this to do a thorough analysis of your results:
http://tinyurl.com/analyzeyourcatsBut you can get a quick idea by opening up your test results and looking for two things:
(1) Your time spent per question (the Time column). Did you rush all the way through and finish 10+ minutes early? Alternatively, did you spend too much time earlier on and have to rush towards the end to finish - or even run out of time before you did the last question?)
(2) Your score "trajectory" through the test (the last column in the Question List page). Were you higher earlier in the section but then dropped by the end? A lot?
If so, then your raw skills are better than the final score. You're just struggling to put everything together on a test. You can learn to do that.
Even if it turns out that the 360 is your true starting point, you still have a shot of hitting your goal in the 3 month timeframe. You'll need to work a lot, of course, but it's not unreasonable (if you put in the effort).
Let us know what you think after you review the data.