Just some places to get started looking for new clothes:
https://www.historicalemporium.com/wahmaker.php?gclid=CIqhx4DsmtMCFYyJfgodPh8HPQ
http://www.sheplers.com/search?gclid=CL7665fsmtMCFYWUfgod_OUNMA&q=Frontier&ef_id=WOJ_NwAAANV_ghLB:20170410213601:s
http://www.culturedcowboy.com/wahmaker/index.htm
http://www.vintagewesternwear.com/Wahmaker-Men-s-Old-West/