My concern is that I noticed that when I accidentally set my alarm (or my kids) that it sometime takes 5 to 7 to get the call from the central answering station. If something were to happen I could a police taking about 15 minutes to occur. I think a thief could do some damage in 15 minutes.

(I have three inside motion detectors and window and door contacts)

I am thinking of way of supplementing my alarm system. I was think of installing motion detector light on the outside of my home.

Any other thoughts on helping my alarm system?

Alarm response will vary from city to city but with the high false alarm rate police do not make it priority one unless the alarm is verified with audio or video from the premise .The average response time with out verification is 45 minutes on average but only seven minutes when your central station can hear or see intruders. Alarm verification ordinance are poping up in a lot of cities across the country where the police only respond to a verified alarm and could be in a jurisdiction near you soon so I would advise you to contact your monitoring company and ask what you can do to get verified.