Here is some infos
Subway map
http://www.tokyometro.jp/station/common/pdf/rosen_eng.pdf
location directions from a good post
http://www.head-fi.org/t/601337/tokyo-fujiya-avic-spring-festival-may-12-2012/30
Please note that the directions in the google map takes you to the back of the building, so you actually go past it on that map.
I took a screen shot of the entrance, I went in through these doors last time.

Its super easy to get around in Tokyo via subway. When you get into the subway station you just buy the fare from a machine, look for the "English" button on the screen, touch it and it will change everything into english and you can buy the correct fare.
iPhone users! please read.
http://www.wireless.att.com/learn/en_US/pdf/Travel-Tips.pdf?source=ECV4IS0000000000U&wtExtndSource=wirelesstraveltips
Hope you can make it.
ken