GMAT Strategy

I enrolled in a Kaplan Course in Israel with their affiliate called Kidum. We just took our first exam, one week into the course (we've had one verbal lesson and one quantitative lesson). So far the course is very professional and the instructors seem to be brilliant at what they do.

I think the exam they gave us is GMATPREP test 1, but I'm not certain.

I really suprised myself positively with the result - v38, q44. Overal 670. I just started studying.

The reason the grade surprised me was that the exam was REALLY hard for me and I kept finding myself deliberating between two questions. I guess I was lucky to pick the right ones most of the time.

When I clicked the "show grade" button I was absolutely certain I would be no where above the mid five hundreds. How do you know in the real exam if you want to see the grade? I can't think of any way to estimate how well you did.

Another problem I am concerned with is that with the exception of one person, everyone else in the course scored below 600 (some in the 400's). I'm concerned this will lead to a situation where the course focuses on mid level questions and not on hard questions, which may not benefit me as much.

I would really love to hear from people who have been studying for the exam and had good scores on their first sample tests.

How likely is it to improve when you start with a relatively high grade?
Is GMATPREP indicative?
Is there any book you would recommend to study which is good for specifically high level questions?
Does anyone have any tips about knowing whether or not you want to see your grade at the end of the exam?

Thanks and good luck to everyone else who is studying!

Gil