Whether you reuse practice material or not depends on why you're retaking the test. For me, I retook the test because the first time I completely clammed up, couldn't stop shaking, and got 4-5 points lower than what I was getting during practice. So I reused nearly all my material while throwing in a new book or two. Result: my MCAT score went up 4 points. But again -- that's what I expected to get the first time.
Where are you standing? Did you expect to get a higher score? Or did your practice exams predict the score you got? Honestly, your score is not bad. It's actually very good because of the balance. I have friends with scores similar to that who have gotten many interviews and many acceptances.
If you're looking to seriously improve your score, you'll probably want to change your prep materials. Using some old books is just fine, because it'll let you review your mistakes and teach your brain how to solve those problems you got wrong. But you need new material to assess whether you're actually improving or if you're just remembering the answers.