You'll almost certainly want to postpone your test date.
I'm not saying that because you're struggling with IR. I'm saying that because you say you have not yet taken a full-length test. That means that you have no idea how you'd really score on the real test.
Whatever level you're scoring right now (about 1-2 weeks before) is roughly what you should expect to score on the real test. Things do not change that much in a week or two.
So your very first task is to take a full-length practice test under 100% official conditions: all the sections, length of breaks, etc.
See what you score is and how far it is from your goal. If your score is already where you want it to be, great: take the test as planned. If it is not, then postpone - you're not going to make any major changes in the next two weeks.
Next, that will also tell us how much you need to do for IR. Are you applying this year? Most schools aren't using IR this year, so we're advising people to go for a score of 4-5. Maybe you can already do that and so you won't need to do any more prep for IR. (But we can't know for sure till you take a test and we see the results.)
After you take your test, use the below to analyze your most recent MGMAT CAT(s):
http://www.manhattangmat.com/blog/index ... ice-tests/Then come back here and tell us the results of your analysis and what you think you should do based on that analysis. (Note: do share an analysis with us, not just the raw data. Part of getting better is developing your ability to analyze your results - figure out what they mean and what you think you should do about them!)
Then we'll figure out where to go from there.