[rbarrios]

well, I would call onstar- have them unlock the car- and look in the car for the keys... just in case.
But you may have luck- and pay less by looking on ebay for a FOB.
As for the key...
Grab your vin- and head to the dealer- they can get you one.
They most likely will want proof that you own the car.
It may be pricey for the key