In a bowl, combine gelatin and sugar; set aside. In a saucepan, bring cranberry juice to a boil. Remove from the heat and pour over gelatin mixture, stirring to dissolve. Stir in the cranberry sauce. Chill until slightly thickened. Meanwhile, in another bowl, beat cream cheese, sugar, milk and vanilla until fluffy. Fold in the whipped topping. Spread evenly into pie shell. Beat cranberry topping until frothy; pour over filling. Chill overnight.