No worries, theres a bunch of places. Dont know which district you live in though. In Puxi Find Big Bamboo bar (address in chineze in any entertainment mag, its on Nan Yang Lu) Take a left as you leave the bar and you will get to Xi Kang Lu. Turn left on Xi Kang Lu, Go over the first cross and keep heading in the same direction. you will reach a small drug store on the right hand side of the street (100 meters max). Quite easy to miss but it has a green cross mounted on the wall, just keep your eyes open. 1 tab 128 RMB / 5 tabs for 500. Any problems finding it just hit me back,
Enjoy!