I'm never consider to take a taxi from Pudong to Hangzhou. The fare is no less than 800rmb. So, if your flights arrive on time, you may catch the last coach leaving for Hangzhou at the airport. The departure time is 7:30 pm and the fare is 100rmb per head.

Another easy way is taking train to Hangzhou. Firstly, you could take the airport shuttle of Line 7 to Shanghai South Railway Station. It takes about 40 minutes on the way and 20rmb. The time should be around 8pm. Then, you may catch D475(8:10-9:53pm/70rmb), N423(8:50-10:48pm/25rmb), K287(9:00-10:59pm/30rmb) to Hangzhou.