No, afraid they're not winter hardly. Even down here in the south of England mine get killed by the first frost. Sad though it is to have to remove the last vestiges of colour from the garden, if you want to over-winter them indoors, dig them up now and pot them in moist compost. You can probably leave them outside for another couple of weeks if the weather is warm, but to improve their chances of indoor survival if you don't have a greenhouse and intend to keep them on window ledges. I suggest you prune them hard back. The roots will be shocked at being dug up and repotted and the less bulky the plants are, the better chance they have of surviving this shock. Once indoors, water them lightly. The major problem keeping them indoors over the winter tends to be whitefly building up on them which can sap the plant's energy, so if you see this happening, shower them off.