I don't know of any courses in New Zealand that take place over only 2-3 weeks. We do occasionally hold a "GMAT Boot Camp" in NY that meets daily for 2 weeks... but that's in NY. (And I really only recommend that for people who have no other choice - it's really hard to cram for this test.)
So there are two big questions here:
what resources to use and
how to study.
What to useWe do offer a self-study package that includes tapes of all of our classes, so people can basically replicate the class experience on their own schedule. You don't have live instructors with whom you can talk and ask questions (that's a big part of the reason why the self-study package is a lot cheaper than the course), but otherwise, it offers everything that a regular course has.
I think it would be challenging to do every last piece of the course in only 3 weeks, but you could get this package so that you can pick and choose which items will be of greatest benefit to you. You can also buy some things piecemeal (eg, individual books), but you can't get access to the class tapes individually - that has to come with the package.
You also definitely need to get the Official Guide (OG) books; these are from the makers of the real test. If you sign up one of our packages, these are included, but you can also buy the books by themselves. Definitely get The Official Guide 12th Edition. Given the short amount of time you have, you may not need to get the other two (Verbal Review 2nd Edition and Quantitative Review 2nd Edition).
Also, go to mba.com and download GMATPrep, the free official practice tests. If you had months to study, I would tell you to incorporate these into your practice test schedule. You only have a few weeks, though, so I would use these as an additional source of practice problems but that's it. (GMATPrep doesn't give you any data to analyze your performance, and you need as much data as you can get in this limited timeframe, so GMATPrep isn't the best source
as a full practice test in your situation.)
How to studyIf you've signed up for our free exam then you were also given access to a free e-book called The GMAT Uncovered. If you haven't signed up for the free exam, then sign up so that you can have access to this book. It gives a lot of good background info and ideas.
You can also use the below articles to help you set things up.
To set up a study plan:
http://www.beatthegmat.com/mba/2010/02/09/developing-a-study-planTo analyze a practice test:
http://www.beatthegmat.com/a/2009/09/23/evaluating-your-practice-testsTo analyze individual problems:
http://www.beatthegmat.com/a/2009/10/09/how-to-analyze-a-practice-problemFull archive of articles:
http://www.beatthegmat.com/mba/manhattan-gmatOne last thing to think about: 3 weeks is not much time. Most people study for 2 to 4 months for this test. If you don't need a ton of improvement, if you have a lot of time, and if you generally "get" standardized tests (have done well in the past, are able to teach yourself easily for these kinds of tests), then you may be fine. Otherwise, you may need to either spend more time or lower your goal score. (For example, I will sometimes talk to people who want to improve 100+ points in 3 weeks. Some people can accomplish this, but this is not typical - it's like seeing the "new diet secret!" ad in which someone says they lost 10 pounds in a week. Someone really might, yes, but most people aren't going to. :)
