You can also use a C-clamp. Just place one of your old pads over the piston and tighten up. Just make sure your boot doesn't bulge out or else it could damage the boot.
http://www.g6ownersclub.com/forum/attachment.php?attachmentid=1450&d=1287270292
That was taken pretty much directly from the "How to change brake pads/rotors thread."
http://www.g6ownersclub.com/forum/attachment.php?attachmentid=1450&d=1287270292
That was taken pretty much directly from the "How to change brake pads/rotors thread."