Bus schedules from Huangshan (Tangkou) to Hangzhou

I am going to visit HS on May 2016. Please tell me all of the daily time schedules for the buses that go direct from Tangkou bus station (not Tunxi) to Hangzhou city and how long is the bus ride? Are the express buses available too ? From which station I can catch the bus? Do I need buy the bus ticket a day before? Thank you..