well, this is not the most profound answer you're probably going to get, but it appears that your current "actual" score estimate would fall somewhere between 450 and 530. :/
in any case, your test date is approaching quickly. this means that, if you've not already, you should take the OFFICIAL practice tests (the gmatprep software tests, downloadable from mba.com or available on cd when you register for the exam). because those tests are official, they'll give you a slightly better idea of where your current score band lies.
note, though, that ANY test, including the official practice tests (and the gmat itself!), features considerable variation. the official line on the real gmat is that the "standard error" (roughly the same as standard deviation) of the exam is 30 points, which means that, if you repeated the test hundreds of times, then 70% of your scores would lie within 30 points on either side of your "true" score. still, think about the flipside of that statement: that means that fully 30% of your scores would be MORE than 30 points more than, or MORE than 30 points less than, your "true" score!
with that in mind, then, it's clearly impossible to suggest one number as a "true" score at the moment. so my answer above, which may have seemed a bit flippant, is entirely serious: you should think of where you're at right now as a
range, not as a single point on a number line.
as far as general study tips, especially for the quant section, check out the advice in
this thread.
finally, you mentioned the og 11th edition second out of the two books you mentioned. while that could just be random - i.e., you just listed the books without thinking of the order in which you listed them - it seems to indicate that you're thinking of the og11 as a secondary resource. if that's the case, then you should realign your priorities so that you think of the og11 as your PRIMARY resource, and the sole source of
conclusive evidence of rules, preferences, and the like (especially on sentence correction, the only area of the test on which there are legitimate debates about which rules work and which don't). this is not to say that you shouldn't use any other resources, period, but rather that you should consider any other materials you have as purely
supplemental to the og11.
and in the unlikely event that the official guide disagrees with some other reference book (especially on stupid little idiom/usage issues on sentence correction), it goes without saying that the og11 wins.
