Here is the bus timetable for the highland express that runs between Hakuba and Nagano during the winter. The starting date is the 17th of December to March the 20th. My preferred choice of travel to Hakuba is to catch the bullet train from Tokyo to Nagano and then the bus to Hakuba, When you arrive in Nagano you turn left after the ticket check stalls and walk about 50 meters and then turn left again at the bottom of the stairs. (there is an elevator also) From here you will see the bus terminal on the ground level. The Hakuba bus stop is number 26. You can purchase the tickets on the bus however you can only use 1000 yen notes and coins. You can also pre-purchase at the gift shop under the stairs when you walk down to ground level. There is a discount for a book of 4 tickets which can also be used on the return journey.
The bus actually runs on a similar timetable for the rest of the year however there are less services so if you are coming during other times just check with your accommodation if there are any changes.
Ticket prices are:
Adults (12 years old and above) 1800 yen
Child ( 6 -11 year old) 720 yen.
Locals tip. If you are travelling on a clear day check the view out of the front window as you come out of the long tunnel after the toll bridge. You will catch the first glimpses of the Hakuba range.