Hiya mate.
409 is R22 R124 and R142 at 60% 25% and 15% respectively so for to time being you are ok to use and continue to use till about 2010 or 2011. I personaly don't mind 409 because it is one of the better drop in gases but I see your point about updating the kit. Try talking to them and explain the cost effectiveness of upgradeing and if you get no joy then put a good price in.

Cheers taz.