Hello Eileen,
The only place you are likely to get a foot control and lead will be on ebay, the sew-tric is very old and if you can get the foot control it will have an asbestos block with a coil of wires wrapped around it for the control, If you are going for a control I would advise a complete motor and control otherwise it will be false economy.
Ken
drivewithken, December 2009