More info would help. Are your bindings still mounted? Are you trying to remount in the same place, or fill with epoxy?
They make a tool to get heli-coils out of there. A small flathead and some needlenose pliers could work too. Pop the top winding of the coil with the flathead, pull with the pliers.
Ahhh. That's easier.
You need to take a dremel to the screwheads and grind them off.
Or, use a powerdrill and drill through the center of the screws with a 3.5mm or 4.1 mm bit. Make sure you are dead center on the screws if you use this method.
If you have absolutely no access to any power tools, a hammer and chisel might work to pop those heads off there, but might also break your binding if you fuck it up.