Most people study for 3-4 months for 2-4 hours a day. Very few people score 750+ (by definition - 750 is the 98th percentile, so only 2% of all test takers score at that level or better). That's not to say that you can't score that well or that you can't get the score you want in 6 weeks - but I just want to let you know that you are both going for an exceptionally high score and trying to do so in less time than is typical. That's going to make it extra-hard.
Also, most people I talk to compare the amount of work needed to taking a regular, semester-long, university-level class. As such, it's going to be necessary at some point to set some priorities in terms of what you study and how you study.
The place to start is with a practice test. You need to know where you stand at the start before you can figure out what you need to do and how you want to do it. The difference between your starting score and your desired score, as well as your individual strengths and weaknesses, will help you to determine the best study plan for you.
You'll then need to make a general decision as to whether you want to study on your own, with friends, with a class full of other students, or with a tutor. If you study on your own or with a friend, start by checking out the Resources area of this web site for ideas about developing a study plan. If you decide to take a course or work with a tutor, start checking out any free sessions or offerings made by any companies in which you're interested and see what you think works best for your goals and learning style.
One thing I do want to caution you about: the quality of your study is far more important than the quantity of your student. Don't make the mistake that so many others have made in the past and think that doing tons of problems and taking tons of practice tests will get you to the score you want. Simply doing lots of problems and tests provides only marginal improvement. You actually need to study the test - both the material tested on it and the test itself (what you're expected to do for the different question types, how the questions are worded, how to recognize what a question is really asking you or telling you, how to spot and avoid traps, how to manage your timing, etc.).
Good luck - let us know how it goes!

















