Nice job on your practice test! We track our students' official test scores against their final practice test scores and the standard error is about 50 points. That means that most students score within 50 points of their final practice test score on the real test.
You will be more likely to score close to or above your final practice test score if you took the test under full official conditions: essays, two 8-min breaks, all in one sitting, etc. If you deviated from the conditions, especially in a way that would give you an advantage (eg, skipping the essays, taking longer breaks), then you are more likely to see a reduced score on the real test.
You can get two free GMATPrep tests from
www.mba.com; these are made by the official makers of the test. Generally, people like to save these for close to the end of their study time. Also, the last time I checked, you had to sign up for the test in order to be able to download these; I assume that is still the case, but you should check mba.com to see.