How original do you want to keep it?
I believe the pump can be rebuilt.
Where is the leak? Around the shaft or from the cover seal?
If cover seal, remove cover, clean up and dry, reseal with silicone.
If around shaft, from vague memory you can remove the pulley, remove the top cover, push the shaft and impeller assembly up and away, possibly remove a washer that hides the seal, replace bushes and seal. These are probably generic parts you can take to a bearing shop and get them to match your sample.
There is a slim chance I have one here to look at and jog my memory. (but I doubt it.)
If it were my machine, I'd fit an electric pump. You'd have to dodgy up a switch to turn pump on and off.