another pad. Unless you have a fancy inflatable pad that has a verified R value of 4 or greater. That alone would probably be sufficient too.

Also, big pro tip here: take a 1 liter Nalgene style water bottle with the screw top lid. Fill it with hot water right before going to bed and stuff it a large sock you're willing to stretch out. Then stuff it in your sleeping bag with you. Hold it close to your core or between your thighs and that will go a long way to keeping you and the inside of your bag warm. Make sure lid is well secured so it doesn't leak. Beyond that, you'll have water that's not only not frozen in the morning but still somewhat warm that will come to a boil fast for any hot breakfast and beverage you may plan to have in the morning.