Jacquie, so sorry! A potted plant doesn't have the benefit of ground warmth that can save ground plants, but I wouldn't rush to throw the pots out. It wouldn't be out of the realm of possibility that they could grow back when they warm up, if the roots weren't frozen solid.
When I dug this patch of plants up from my Mom's yard, they sat in a plastic storage tub for a few months, through several frosts, with bare roots. Everything was still alive when I brought the tub home in the spring to add to my compost pile (after sending as many plants to people as wanted them.)
