Where to find a bus sheet of jingjiang to Shanghai and which Shanghai bus station is the most convenient to visit Shanghai?

Hello,
I'm in China for work since some weeks in Jingjiang, Jiangsu province. I'd like to go for one day trip to Shanghai, next Sunday. Do you know where I can find a bus time sheet and which Shanghai bus station is the most convenient to visit the city? Will it be difficult to buy a ticket during this period (spring festival..)? Do I need to book it and where?
Thanks