I used to have a Vantage Pro, but can't really help you. I can't imagine that you need to get a better unit unless it was an upgrade to a better Vantage.
Have you tried checking the Vantage website to see if they have a support email?
Also, it may not be a bad idea to check here:
WXForums Davis Instrumentation Weather Stations subforum.
__________________
Steve
'08 Boxster RS60 Spyder #0099/1960
- never named a car before, but this is Charlotte.
'88 targa
SOLD 2004 - gone but not forgotten