Most of it is National. The bobbin winder looks German. There are lots of National parts on ebay and Bonanza. You just want to make sure the slide is from the same model as yours. You want the short National shuttle and bobbin compared with the long. The long is not common except as Boye brand 22. The short is Boye 13 if you prefer new old stock to used. The rubber tire on the winder engages the handwheel. The winder needs a new tire and a cleaning so it turns easily. Here is a good National model reference:
http://needlebar.org/cm/thumbnails.php?album=260&page=5
Jon