Three hours is very tight. It needs about three hours from Pudong airport to Hangzhou airport by taxi. However, the fare will be very expensive. The other faster way is you should get to Shanghai South Railway Station and buy the ticket of trains Z115 at 19:52 and arrive in Hangzhou East at 21:16. Then take a taxi to the airport at once. You need at least one hour to Shanghai South Railway Station and at least 45 minutes from Hangzhou East to Hangzhou Airport. It seems impossible to get there on time.