Check your "Profile" on Planet Auran to see whether you have any discount vouchers to use. Auran do give them, and there is a system whereby people who don't need them can transfer their unused ones to you.
I don't understand what you mean by "Impulse version" though-if you've bought from a third party provider rather than direct from Auran you won't get a discount unless that provider has a scheme.
I wouldn't really worry about upgrading as 2009, with it's service packs, is not much different from 2010-if you're a new user, get used to 2009 for a while.