There is a cream whipper you can buy - we had one when I was a kid - 50 years ago - and I bought one when we were stationed in Germany - it uses small CO2 cartridges - you pour the cream in a metal jug - screw on the top - screw in the gas cartridge - and voila! whipped cream - and it stays fresh in the fridge for a LONG time.

Here is a link to one on e-bay so you can see what it looks like
http://cgi.ebay.com/ws/eBayISAPI.dl...&category=20642