[nst7]

You may need to be more specific.

You can upgrade to Ultimate right now with your current system and it will work fine, since your non-Ultimate version is working fine. Just like non-Ultimate, it will work with various brands of interfaces, or the built in output, etc. It will just give you the extra features it contains.

Now if you're looking to upgrade to a Protools HD system with hardware and everything, then as was mentioned, you may want to talk to a dealer. There are still many different variations you can do.