You are in luck. There's a Philippines Statistics Authority office there:
PSA Building, Diosdado Macapagal Gov't Center Barangay Maimpis, City of San Fernando, Pampanga 2000
You can walk in without an appointment. You each fill out a form (take your passports and any Phils ID your wife has) and hand it to the cashier and pay a small amount (I can't recall, maybe p200 or so). Then sit down and wait to be called to the "Releasing" counter. There, you will get your Cenomar, or, maybe a surprise...a record of marriage. I'll take it your wife has no record there. The whole thing might take 1-2 hours.