Napa for New Years
Normally I don't tell people to search the board but right below your post, one half hour before you posted was this thread.
Just clicking on the SF board it would be the first thing you look at. Did you notice this or is nothing on that list anything that interests your?
There are menus, hours, prices of about a dozen wine country restaurants serving special New Year's menus some of which are in Napa.
That being said, it would be unusual for anything, especially a wine bar, to be closed on New Year's Eve. Pick a wine bar, any wine bar that interests you.
If you want music and all that, La Toque has a beverage and dessert bar party. The Napa Wine Train has a party at the station limited to sparkling wine and sweets. More info and links to these venues are in the link at the top of this page.