Spread the ice cream evenly in the pie crust. Cover and freeze for 2 hours, or until it is completely firm.
In a large bowl, combine the pumpkin puree, sugar, cinnamon, nutmeg and ginger. In another bowl, whip 1 cup of the cream until it forms stiff peaks. Fold the whipped cream into the pumpkin mixture. Remove the pie from the freezer and spread the pumpkin mixture evenly over the ice cream layer. Cover and return to the freezer and freeze for an additional 2 hours.
Minutes before serving, remove the pie from the freezer. Drizzle the caramel sauce evenly over the top. In a bowl, whip the remaining cup of cream until stiff peaks form. Cut the pie into slices, and top each slice with a dollop of the whipped cream.