First thing I would recommend is to get some training from a certified handgun instructor. Being a police officer DOES NOT qualify someone to teach firearms, and it doesn't even mean they know much of anything about firearms at all. I have seen police officers who were absolutely abysmal shots and didn't how to properly hold a handgun. I've also heard some of the worse firearm advice from police officers.
I'm not saying that ALL police officers can't shoot and don't know anything; I've known some police officers who were VERY good with firearms and very knowledgable too. But I'm just saying that you should NEVER take the firearm advice of a police officer simply because they're police officers.
It's actually a very common problem for new shooters to rely too much on the "expertise" of police officers and military members; the problem is they're less skeptical when they receive bad advice because they have a misguided trust that those people must know something about guns, even if they don't. I made a thread about this very subject a while back:
http://thefiringline.com/forums/showthread.php?t=508860