Wow, David have you been having really warm winter weather like we have? I'm harvesting ripe tomatoes these days!
Sunflowers are annuals, i.e. they complete their life cycle in one season. So if you have the energy to bring it indoors when the nights get cold, and put it out again on warm sunny days you might keep it alive until it matures. Not sure if you'll get seeds, though. That would depend upon if it gets pollinated or if your bees have decided it really is winter.
