Don't focus too much on your estimated scores. Try to see why you're getting the questions wrong, was it misunderstanding of the question or a gap in knowledge? The real learning comes from reviewing the exam and the questions you missed, marked, or were unsure about. Completing sets of practice problems won't improve your scores nearly as much as reviewing your mistakes and learning how to avoid them.
If you're missing questions based on a knowledge gap, go back and review your notes for the topic or concept. Figure out what piece of info you were missing and include it in your notes. If you're missing questions based on a misunderstanding of the question itself, try adjusting your test-taking techniques. Always step back after reading a question and figure out what they want, then solve. If you're running out of time, mark the hard questions and answer them last to ensure you get all the easy problems right. Lastly, I highly recommend taking the 2007/2009 DAT practice tests too, they'll be the best indicators of your performance.