And the booking office is busy, go directly to a ticket machine and buy any cheap ticket (150 yen), this will get you in the station, then board the train. (In Japan it is quite acceptable to buy a ticket on the bullet train).
If you are visiting more of Japan then grab a Japan Rail Pass. This can be used on JR lines in Tokyo such as the Yamanote loop line. When I went I used it all the time to get around the city, which saved significantly on travel. It is only worth getting though if you are going to be travelling beyond the city, otherwise it's rather pricey.
Available in Japan at major railway stations for various time periods (eg 7 days, or a month).
Snow Japan is an awesome website that makes leaving Tokyo for a day or more to go out and enjoy skiing and snowboarding easy for everyone. The site itself has as much info as you could want about resorts and things, but it's the popular forums and growing community - and the things that people submit to the site (reviews of resorts, photos, online diaries) - that really make it extra special. A fantastic resource for anyone living in Tokyo (or anywhere else for that matter!).
Send your feedback or queries to email@example.com