Nen ga Jyou

Hello friends, my new boss from Japan is visiting my country and i had never met him before. Also he is returning to Japan within a week, which is couple of weeks before New Year's day. Can I give a New Year's card (nen ga jyou). Is it ok for me to give new year's card to my superior and that too 2 weeks ahead of New Year's Day........

Also how to say Advance New Year wishes?

Nengajou is only to be given on or after the New Year's day.
If you're meeting him 2 weeks before and want to give some greeting card, maybe you can give him a greeting card wishin him a happy new year in western style, then it does not look out of place.

As to the greetings, you can say "douzo yoi otoshi o" (if you want to sound politer, "douzo yoi otoshi o omukae kudasai").
(Literal translation is "please receive a good new year", meaning I wish you a Happy New Year".)

This greeting is best to be said on his departure. It is not to be said when you meet someone.

Raj,

It is not normal to receive New Year cards before the New Year, and it is not normal to give them by hand.
I would recommend following the customs of your own country. Or why not give a non-religious "Season's Greetings" card and include in it best wishes for the New Year?