You need to find out exactly what they require in the PT exam. Then focus on mastering all of those discipline. For example, if they require 25 situps, 25 pushups and 1 1/2 mile run in 30 minutes - then focus on mastering each one, one a day. Then when you master one each day, do two a day and three a day up until you can do everything in one day and keep doing it in one day but be sure to throw some rest days in there as well. Not only will you likely pass the PT exam but you will likely lose some weight and get a lot stronger in the process.
If you are not a big runner, I suggest you check out the Couch-to-5K program. It is a great for beginner runners!