Roxanne, I think you'll regret it if you bring them in for the winter. They won't stay tadpoles in your aquarium, don't forget. You'll be dealing with frogs living in your house all winter if you do that. You have a cat, (cute little bat-cat in your avatar) so . .. that's another hazard for frogs.
They'll be frogs in a month and will be able to take care of themselves. I'm sure the water won't get that cold before they have their legs and can crawl away to hibernate. If the weather turns cold suddenly, just leave a hose out in the sun, and add warm water on sunny days whenever you can, to keep the water temperature in your pond up a bit longer.
If you would fill in your location on your personal profile, we'll have a lot more information than just a zone. This helps to advise you. Your profile can be found in the blue toolbar to the left, at the top. The little person icon. Zones only tell us your "average" coldest temperature in winter. Not when it first frosts, or how long you might have a warm Indian Summer .