Soften unflavored gelatin in 1/2 cup water; set aside. In 3-qt. saucepan, combine cranberries, sugar and wine or cranberry juice; heat to boiling, stirring occasionally. Reduce heat and simmer 5 minutes, stirring frequently. Remove from heat. Add lemon gelatin and softened unflavored gelatin; stir until dissolved. Stir in remaining water. Chill until mixture is partially set. Fold in celery and walnuts. Pour into greased 8-cup mold; cover and chill until set. Meanwhile, combine sour cream and mayonnaise; refrigerate until ready to serve. To serve, unmold gelatin and top each serving with dollop of dressing. Garnish with celery leaves.