I was just a day or two in Osh in 2012 and didn't see any, but wasn't really looking. I found it an odd place, good in parts, crappy in others.
There may well be an outdoor store there, but otherwise check with one of the main agencies like Ak-Sai, or ask at https://www.facebook.com/redfoxoutdoorkg/ which is the main outdoor shop in Bishkek.
We have always been told that they are basically impossible to find in Osh. So we have ended up buying them in Bishkek and transporting them overland from there. Good luck!
Maybe you can get an agency like Ak-sai to send some gas to Osh. Buses and taxis often function as couriers in a lot of countries I've visited. Think that might have included Kyrgyzstan.