Hofner 500/1 CT replacing parts?

I have a Hofner 500/1 Contemporary Series and want to replace some of the parts with the actual German ones. Where should I start looking, and about how much would they cost?

If you're near Toronto, contact 12th Fret in the east end. They sell their Contemporary bass with Hofner strings and teacup knobs upgrades.

http://www.ebay.com/itm/Hofner-Style-Tea-Cup-Knobs-Set-of-2-/160718499001?pt=Guitar_Accessories&hash=item256b91acb9#ht_670wt_907

http://www.allparts.com/Vintage-Hofner-Style-Tea-Cup-Knobs-p/PK-3280-000.htm

http://www.voxshowroom.com/northcoast/hofner/hofner_parts/index.html