^^ agreed. You're going to be up against some stiff competition, so having scores well above the minimum would be best. In addition to the books mentioned by cj, check out the ASTB threads on here, there is a lot of really great gouge. Also, the physical readiness test scores are not submitted with the initial application. They are part of the documents that are submitted after one is professionally recommended. So they would not have any bearing on your pro rec, just final select.* You have 30 days to study- retake the ASTB, rock it, and do as much as you can to make your application strong. Best of luck!
*disclaimer- This is valid if you're applying for Navy OCS. I don't really know too much about the application process for the other branches, things may be different.