Convert it to electric!? ..... EWWWW Yukapooie
Yes, it can be converted to electric if you must. They are incredibly simple to do. Sew-Classic makes complete aftermarket kits to do it with ~or~ you might find an original Singer motor - light - controller set up that would bolt right on.
If the cabinet and machine were in reallly reallllllllly great shape, had the attachments and owners manual, I could be convinced to pay his price. But I'd offer him $75.00 to start.
JMHO
Joe