You say, correctly, that you don't want to study algebra for the sake of algebra, but you want to stay focused on the GMAT. You have hit on one of the key problems with self-study. Because most people do not have extensive experience with the GMAT, they study material widely out of the boundaries of the test, or material that is so very restricted, it misses the more "foundational" types of questions on the GMAT.
GMAX Online was specifically designed to teach the material within the entire scope of the GMAT, not leaving anything out, and not broadening it beyond the test. The methods used begin each topic from the start, so the student truly learns the foundations of the material and can do the hardest questions on the test - the ones that demand complete understanding of the subject and not just some tricks or formulas. The GMAT course is long: many students study with it for more than 80 hours. And there is extensive homework that should be completed. But because of the unique style and delivery methods (check out a few demo lessons on this website under "test prep reviews" for GMAX Online on the home page - you'll find links to the demos about half-way down the review) students do very well. There are posts in this forum, and in others, of students getting well over 700 just with GMAX.
Since all your grades are visible to the universities when you apply, it is very important that you take this test seriously and do not show a poor grade - even if it is your first grade. Some universities assume that you know they will see all your grades and that they will receive and read your GMAT essays. So study properly, and do not go for the test until you know that you will do well.
The best of luck.
Director, GMAX Online