Based on my understanding on reading your problem, you are trying to do two things with a single script.

I may go for,
For first point - Schedule a cron job for every minute and do the monitoring stuff using perl script (you may select monitor option while running the script by passing argument as monitor)
For second point - Schedule a cron job for every 30 minutes and send alert email using perl script(you may select alert option while running the same script by passing argument as alert)

For last one "how to convert it into exe" - Please use PP you can look into one of the recent post by marto here
Re: How to convert bunch of perl file + other dependent Input files Into a single executable