You should take airport bus to the city center of Hangzhou, Wulin Square. Then take a taxi to Hangzhou East bus Station. take bus to Suzhou, 2-2.5 hours. The station in Suzhou you are arriving has bus to Zhouzhuang, but the last bus will leave around 17:10. So, I think you may mis it. If you want to get there the same day, take taxi. The taxi fare is about 150-200RMB, I think.