Kinokuniya Bookstore is hands down the best place to find untranslated Japanese books as well as Japanese music, movies, etc. Below is a list of the cities that have Kinokuniyas in North America.New York City, New York
Los Angeles, California
San Francisco, California
San Jose, California
Seattle, Washington
Costa Mesa, California
Beaverton, Oregon
Edgewater, New Jersey
West Nyack, New York
As for what to read, I recommend anything by Haruki Murakami. For something short and sweet read Kitchen by Banana Fujimoto!