sorry for the late reply
you can fit an original VW auto but the problem is that ideally (due to the added weight etc) you woudl have to fit IRS (independant rear suspension) as well. This can be done very easily by a skilled mechanic as long as you can find all the donor parts from another car but the easier way would be to get a 1302 or 1303 or even more ideally find an auto car which has been converted to manual some time in its life. all US spec beetles after 1968 had IRS as stock, this was not the case with the rest of the world till around 1973.
the auto is a 2 speed and i'd suggest getting at least a an AR (1300cc dual port), H (1500cc single port) or AS (1600cc dual port) engine fit to it so that you can keep the car usable on all terrains and on difficult inclines.
the auto is more like a manual auto as you have to change gears with your hand but you will not have to use the clutch (as it is not there).
good luck