Mrs.Koh,

You can reserve the ticket two days in advance. Here is the telephone: 021-63771917、63770961and 63769868. I am not sure if the staff there can all speak English. You can also check this page to learn much into (including the ticket fare and admission fee):
http://www.chinassbc.com/english/bestline/?id=1

The bus departs at 7:30 am from Shanghai Stadium and gets back at 14:45 pm.