There are other organizations in and around Tokyo that you might consider as well. Two that I personally have trained with Kobayashi Yasuo and Kazuo Igarashi, are well worth your interest. Check out their websites, or you can look them up on the Aikiwiki. Several of Kobayashi's student's train at Hombu Dojo as well as at his dojo.
http://www.cup.com/kobayashi-dojo/english/index.html
http://home.att.ne.jp/moon/igarashid...h/english.html
joe