Hello. My pgwp is expiring in September, but I am eligible for pgwp extension. How long before expiry of my pgwp should…

CanadaPost-Graduation Work Permit1

Hello. My pgwp is expiring in September, but I am eligible for pgwp extension. How long before expiry of my pgwp should I apply for the extension? Also, I am planning to travel out of Canada. Do I need to apply for the extension only from within Canada? Tia