Best prepaid sim card for international calls (Manila)

Hi all.

I will be arriving in Manila (finally) in January and will need to get a pre-paid Sim for my mobile.
I have already arranged global diversion for calls to my Australian number, so I just need a local number to receive those calls on.

However, I will be in Manila for 5 weeks initially and possibly staying for 12 months.....so I need a mobile plan that allows me to make occasional calls back to Australia without costing an arm and a leg.
I won't be making a lot of local calls or texts, but might need about 1gb of data allowance per month.

Globe and Smart seem to be the providers of choice.
Does either of these have a suitable Sim?