New Koi Owner? Help please!!!!!!!!?

Ok, i have two questions. I need to know how to help my fish survive in the winer and how to make them eat. I have 4 koi and 3 goldfish in a 3 1/2 feet deep and about 8 fet around pond, with a waterfall. Note that we are not keeping the koi in there when they grow bigger, they are from petco and about 2 inches. They have TONS of room to swim and underwater caves and cracks and stuf like that to hide in. I am only 13 and my parents wont let us get a tank inside for the winter. Unless i can somehow get a makeshift aquarum than thats not gonna work or winter. Second thing is that they will NOT EAT! They have TONS of algae and gazillions of tadpoles to snack on, but whenever i throw in some of that floating pellet things they wont eat! I aso tried peas and carrots. Dont say that i dont need to feed them caus the algae, but neither koi or goldfish will eat it, and i really want the experience to be able to hand feed. I have had thaem for 3 days and i lu them so much. they alread survived a severe thunderstorm and tornado warnings, if that helps any. oh, and the goldfish where obtained at a pond shop, very nice people there who were very educated. THey werent just random goldfish. THANK YOU SOOO MUCH IN ADVANCE!