In reply to goatee:
I don't recall having seen an outdoors shop in Montreux at all (despite its profile it's quite a small town) but there definitely is one on the lakefront at Vevey (it's called Le Nomade) which is about 10 minutes away on the train. No idea what it sells as I've never been in there (though I've walked past it hundreds of times) but I'd venture it probably does sell some kind of cooking kit.
There's also a sizeable Intersport in the shopping centre where Manor is on Vevey main street.
(Despite the profile of Montreux due to the jazz festival Vevey is a much larger town with far more facilities).
Post edited at 16:42