First of all, report the incident to the manager, and then call the local PD, and file a police report.
As for your cars, I would be sure that they have an alarm system, and park them in a well-lighted area, that is visible, ie not behid a bush that can conceal people doing a B&E. Or if possible, visible from your apartment. Make sure your vehicles insurance policies are in force. Don't store anything valuable in your vehicle. I know one guy who lost his guns because after a Friday night of shooting left them in his car, and his car was stolen early in the morning along with his guns.
As for your own personal apartments, I would have timers, lights and a radio tuned to your favorite TV station come on and off during the time you're away from your place. And you may want to layout some sucker stuff for theives to take JUST IN CASE they break into your place.