Strawberries do die back a bit in winter so this is perfectly normal. Just clean up and cut away any old foliage and plant debris that has accumulated around the plants. Strawberries are perennial so they will return year after year, although it is best to replace them after their third season as they tend to become diseased and lose vigour. The main thing to look out for is that they dont get too wet. Check that the baskets and compost are draining properly to prevent the plants from rotting. If possible put them in a cold greenhouse then this would keep the worst of the wet weather off. Water them very sparingly until the spring when they can be returned to the outdoors. If you dont have a greenhouse, then move the basket to a sheltered position to prevent them becoming too wet. Strawberry plants are hardy and a bit of cold weather will probably do them good, as it can kill off any overwintering pests and diseases!