Andrea,
I agree with Aung in that I would not take more exams until you have had a chance to review the weak areas, reevaluate your study plan and build your knowledge in those areas. I know exactly where you are coming from. I was in a similar situation in which I had taken a few exams and was scoring at or just above where your scores are. At that point I realized that I was not ready to take the actual exam I had already scheduled. So, about two weeks from my exam, I rescheduled it for about 6 weeks later which gave me the extra time needed to really focus and alter my study plan. It was the best $70 I ever spent. I am not saying you should reschedule your exam, but it is an option and one that you should keep in your back pocket. There is certainly no shame in doing so and it is much better than going in unprepared and risking failure.
Mark