GMAT Strategy

I'm planning on taking the GMAT on Saturday August 23rd. I just started studying, so I think this should give me enough time. I'm also going to take Powerscore's Weekend Intensive course during the weekend of August 2nd and 3rd to give me a little boost on anything I couldn't figure out on my own. (Is this a good idea, or am I unnecissarily spending the money? I know that's subjective, but I think I should be able to learn everything I need by August, so I don't know what this course can offer me that I won't learn on my own.) The week after the course (August 7-11 I will be taking a short trip for a wedding. I think this will be good to help me relax before the test. When I get back I'll have about two weeks to do last minute studying. Does this sound like a good plan? Also, is August a good time to take it? I plan on getting my application in by late September/early October. If I need to take the test again, I would be able to at the end of September and still meet my application deadline.