Whereabouts near Tokyo station are you? If you are on the Marunouchi side, then the "Ohtemachi" branch of Citibank is probably closest. It is roughly 10 minutes walk from the North exit (Marunouchi side) of Tokyo station.

If you're just looking for any cashpoint that works, I believe that the Post Office ATMs are likely to work with a foreign-issued cash card.


EDITED -- Oh, now I seem to recall that you mentioned you are staying at the Palace Hotel (Or maybe I have you confused with another person?). Well, that's very close to the Ohtemachi Citibank.

Go out of the hotel - turn right on Eitai Dori, so that you are walking away from the Imperial Palace gate. When you get to the intersection of Eitai Dori and Hibiya Dori, look across to the opposide side of Eitai Dori. You will see an arched entrance to the subway and the Citibank is in the building right next to it.

It must be about 3 minutes walk from the Palace Hotel.