Hi Val,
This is quite an old machine and parts are not easy to find. Having said that, as it is a standard gauge machine, cast on combs made for Brother, Toyota or Knitmaster will do very well.
Ebay is a good place to look for such things.
Hope you manage to find what you are looking for.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix knitting machines.