They don't sell the clips separately. You would have a better chance finding one in the service department at your dealer. One of the mechanics may have one in his spares box that he may give you. Just buy a new master link. In fact, buy two so you have one for the next time you break a clip. Even if you could find a online source that would sell you just a clip, you would probably pay more than the cost of a master link for shipping charges.
Also, if you are breaking the clip on your master link you are installing it incorrectly.