Scores on the official GMAT Prep practice tests are good for estimating how you would score on the real test.
Regarding the missed questions, while missed questions in the verbal section drive your score down fairly quickly, you can miss a fair number of quant questions and still score rather high.
One possible issue to be cognizant of is that the questions have evolved a bit since that practice test was created. So, the questions on today's GMAT, while not exactly more difficult than the ones you saw, will, in many cases, be structured a bit differently from the ones you saw, especially in verbal. GMAT Prep tests 5 and 6 contain questions more like the ones that appear on the actual GMAT today.
Regarding how to move forward, to lock in your high score and possibly score higher on the real thing, review all of the test questions to see how you could have gotten more correct and to find ones that you weren't really comfortable answering. For any that you weren't really sure how to answer or that took a lot of time to answer, learn all about how to answer questions of that type and then answer dozens of questions of that type until you mastering answering them.
By mastering answering questions that you had trouble with on this test, you will fill in gaps in your knowledge and skills.