Currently, I use Avid Xpress Pro and a standard DV camera via IEEE-1394.

If I upgrade to HDV, is there any upgrade I need to implement for the Avid software to recognize the new camera?

As far as I know Avid does not support native HDV yet, or at least
I haven't heard anything about it yet. Did you check Avid's website
for support? If it isn't listed I would not count on it being in there.