Stepan,
Go to http://www.onthedash.com/Guide/_Catalogs/1970_Technical_Manual/?show=Cal11TMPage11.jpg all the technical data for the Cal 11 is there and the parts are mostly interchangeable with Cal 12 page 4 shows diagrams of parts and page 6 descriptions. The part you most likely need is 2556/1. Go to http://www.scotchwatch.com/Heuerparts.html the part is not listed but e-mail Blake anyway as he often has parts which are not listed. Oh and find yourself a good watchmaker with experience of the movement as well.

David