I tend to print maps out from google before I go anywhere here but I am sure the bigger bookshops with a good english selection would have a referdex. The two bookstores I use are kunokuniya in shinjuku and Good Day in Ebisu http://www.gooddaybooks.com/contents/home/index_html?language=english
How about Maruzen next to Tokyo station, the atmosphere is much better than the crowded Kinokuniya in Shinjuku, chairs and tables are available for perusing.
Then nice buffet lunch at Mango Tree(Thai)in Maronouchi building, the food is good, the view is fantastic, but go early.