Line a 9x5-in. loaf pan with a double thickness of foil; set aside. In a large bowl, beat the cream cheese, sugar and sour cream until smooth. Fold in strawberries and whipped topping. Pour into prepared pan. Cover and freeze for several hours or overnight., In a small saucepan, bring the blueberries, sugar and water to a boil; cook and stir for 3 minutes. Cool slightly. Transfer to a blender; cover and process until pureed. Refrigerate until chilled., Remove dessert from the freezer 15-20 minutes before serving. Use foil to lift out of pan; remove foil. Cut into slices with a serrated knife. Serve with blueberry sauce.