why not borrow a coupler and use that? you could rig it up with a picnic tap on the 'out' end, and some form of pump or gas on the in....same concept of the pump. So either use a bicyle hand pump, or CO2 which is best.....
there's a couple of actual pumps for sale in the halifax area on kijiji....if you know anyone down that way..bus would be quickest for shipping if you needed it for the weekend.