You can e-mail to the linked address above or reply here. They are the result of a cross between a hybrid wheaten columbian gold male line and a hybrid silver brown female line with dominant white. Your line will not breed true even if you found some Golden Comet males. These males are mostly white with some gold on them. You can probably cross these hens to any production quality cock and get decent results, but the color will be all over the map.
Comet females are gold because they had a gold father.
If you want to maintain the brown egg shell color get a Production Red cock or a Barred Rock cross. If you cross to show stock your egg production will not be as good. Around Feb and March local feed stores will help you combine orders with other so that you can get just a few chicks. Some feed stores will sell baby chicks in small lots. Check around your area.