My advice would be to begin with the end in mind. I'm in a similar situation... I've been a cop with one state here in Australia and I am in the late stages of an application with a police force in another state, so I have prepared for selection twice now.
The first thing you will need to do is be well and truly ready for the required fitness standards of the police service you wish to join. Get the info and know exactly what they will be testing you on. Prepare yourself to a standard WELL BEYOND the minimum, selection is going to be tough and any advantage you can get is one you should exploit. Being super prepared physically will help you to stand out.
I'm not sure exactly what the standards are in your part of the world. I needed to do a 10.1 Beep test (so I trained myself to be able to do a 12 consistently) a 16.9 second modified Illinois agility (so I trained to do a sub-15.9) and a range of other tests specific to local standards and the equipment used here.
Once you're on the job, being strong physically is always an advantage, as is being well conditioned and being able to handle yourself in a physical confrontation, but the most important thing is knowing how to use the verbal judo so that you don't have to resort to physical means very often.
My advice, train yourself to SMASH the fitness standards required for selection and training and you will be a long way down the right path. Maybe post up exactly what is required and then people much smarter than me can help you figure out the best way to achieve it.
Good luck with your career aspirations and congratulations on your physical transformation so far.