It's not unusual not to see improvement in your overall score while the class is going on. You're getting better at some things, but you're also slower with the things you've only learned recently, and any time you're slower on one thing, that's going to affect your performance on other things. Progress on these tests is not typically linear, in terms of score improvements on practice tests.
I wouldn't concentrate on your overall score at this point, while the course is still going on. (See below for more on what should happen after class is over, though.) Instead, you should be concentrating on your performance across the various question types and content areas. Also, "performance" encompasses not just accuracy but also efficiency and difficulty - so, not just percentage correct, but also timing and difficulty.
Take a look at this article to get a better idea of how to analyze your practice tests in order to determine where you are improving and where you are not improving.
http://www.beatthegmat.com/a/2009/09/23/evaluating-your-practice-testsThis is a 2-part article; click the link at the end of the first part in order to read the 2nd part.
After you've read that and done the relevant analysis, read this article (which is about how to review individual practice problems):
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http://www.beatthegmat.com/a/2009/10/09 ... ce-problem[/url]
So, it sounds like you're about 7 weeks into the 9-week course, yes? So you've got 2 more weeks of class to go, plus 3 weeks after to study? You don't mention what your current scoring level is (just the subscores), but a 40Q, 28V should be in the mid-500s? It may be tough to achieve a 130+ point increase in 5 weeks, especially with only 3 weeks of review after the course ends. You may have to be flexible in terms of your test date. Take a practice test about 2 weeks before and see where you're at; if you need to postpone, you can do so for a small fee as long as you reschedule more than 7 days in advance of your test date.
Also, make sure you sign up for the end-of-course test review with your instructor - and take advantage of your instructor now to ask questions and get some advice. The instructors are often just sitting around before class, waiting for class to start, so that's a great time to ask for advice. S/he should have some idea already of your strengths and weaknesses from class, so s/he will be in the best position to advise you.