Unfortunately there is not a Snowpulse Refill Centre in Valemount or Blue River. We are actively seeking a shop in the area to set themselves up as a Refill station, but haven't had any takers yet.
In the meantime, Kamloops is going to be your best bet (there are several Paintball Shops in the area) for a refill. Probably a good bet to bring an extra canister on the trip and be sure yours is filled to correct pressure before leaving on the trip.