You are still far enough from your goal score that it's unlikely you will hit 650+ in 2 weeks. I agree that it would be nice to be able to avoid IR, but I don't think there's much you can do - if I were you, I would postpone.
Re: your practice test scores, quant started at 34, went up to 41, then dropped back down to 37. Why? Verbal started high, went down, and is coming back up again. Why?
Such variability often indicates timing problems and holes in your foundational knowledge. Ah, okay, just got later in your post and saw that you are having timing problems. So that is one of the problems, at least.
Read these:
http://www.manhattangmat.com/blog/index ... to-win-it/http://www.manhattangmat.com/blog/index ... anagement/translations:
http://www.manhattangmat.com/blog/index ... into-Math/overlapping sets: don't worry about them - they're not commong enough. Know how to make a good guess and make sure you don't LOSE time on these.
Inequalites, roots, exponents, factors - those are all common and important. You say that you're making careless mistakes on these due to the time pressure, so if you fix the timing problem, that will help to reduce the incidence of careless mistakes.
Also, though, ask yourself: what specific mistakes do you actually make and WHY do you make them? What different habits do you need to make in order to minimize the repetition of the same kinds of errors in future? (eg, I used to solve for the wrong thing sometimes, so I changed the way I wrote things on my scrap paper to make it a lot less likely that I would solve for x instead of y.)
Percent and fraction difficulties are usually due to 2 issues:
- translating words into math (addressed above)
- knowing when to go back and forth among fractions, percents, and decimals (in one problem)
eg, it's usually easier to add or subtract in decimal or percent form than in fraction form. It's usually easier to multply or divide in fraction form (since you can cancel). And then you need to think about when it's worth it to convert to one or another. Etc. This comes with a lot of practice and very conscious thought about: what would be an easier way to tackle this? You may have to try a few different things in practice until you figure out WHAT would be easier and then you ask yourself WHY is this easier and how would I know the next time around? What criteria need to exist in order for me to say: oh, fractions will be the easiest way to do this one?
Re: IR, you may want to go and browse through our blog for the various IR articles that have been posted in the last couple of months. They'll get you started. :)