If you can find a Singer controller like the original, the one with the small button beside the raised button and if the controller bracket is still inside the bracket you can make a knee controlled machine out of it.
As far as the controller and wire about 5 feet of 18-2 SPT2 wire, a couple ring connectors and a new foot controller and your in business.
I'd check at your LSMG if you have one for a Singer controller. If he doesn't have one the ones Sew-Classic sells work pretty good. I have about a half dozen of them on my machines.
Joe