You have to swap over the sensors on your new wheels or you will get a light on the dash with a tire pressure alert. If you don't mind the light then I guess you don't have to swap the sensors. I know a few guys that run a second set of tires for winter and they just put up with the light.
Universal bands are avalible for any wheel size. Make sure who ever does the work gets them on tight or the sensors will move around the wheel and you will have balance problems. In the Northwest go see Les Schwab Tires.