Just buy a return ticket, or one where you will be flying out to somewhere other than your home country (ie...an onward ticket).

It is perfectly fine for the departure (from the Phils) date of such tickets to be more than 30...or 59 days after your arrival in the Phils. As long as you have a ticket OUT, that's the only concern of Immigration.

Then just extend your 30 days visa waiver by another 29 days at the nearest Immigration Office, a week or two after you arrive in the Phils. You may also ask to do this at NAIA terminal 1, before going through Arrivals Immigration...IF that's where you're landing.