Obviously the easiest thing to do would be to upgrade what you have. That said, from your first post, it sounds like your Avaya vendor might not be the best. Maube you should explore the upgrade option with another Avaya dealer. There are quite a few Avaya dealers around, as well as many independent installers that know the Avaya product very well.
I have noticed that some of the long-time Avaya vendors (and Nortel vendors, for that matter) have gotten a little arrogant. Soemeone a little smaller and a little hungrier might give you better service.

------------------
Intertel Telephone Repair
Avaya Telephone Repair

[This message has been edited by paul144 (edited December 17, 2004).]