Dear Ms. Jen,
From Pudong airport, take the No. 7 airport-line shuttle bus to the Shanghai South Railway Station directly. It takes you about 1 hour and you only need to spend about RMB20 for one ticket. If you take a taxi, it will cost nearly RMB200. So, if you are not in a hurry, the shuttle bus is a better choice. By the way, the bus departs every 20 minutes.