Get a card from the hotel or ask somebody to write down the street name in Chinese. Alternatively, use your handphone to call wherever you want to go and pass the phone to the taxi driver.
Agencies in Utopia are usually a bit more expansive. As I said again and again, you must stick to larger agencies, otherwise you are asking for trouble. Here is a bad experience when I was in Guangzhou last month (no major agencies in Guangzhou):
I was feeling horny and wanted to find a muscular boy in Guangzhou. I went on various agencies and called one of them. I explained over the phone what I am looking for as I do not trust the photos. The agency recommended a boy, his photo was ok and the owner assured me he is muscular. If I do not like him, just give him taxi fare and send him back.
When the boys showed up, he was entirely different from photo. Look was not that important, so I asked him to show me his body. Totally flat, no six pack, so I sent him back. He demanded RMB100 taxi fare (no way it is so much unless he is the other side of town but he showed up 10 mins after I called, most likely RMB20-30 return by taxi) and RMB200 tips because he show me his body. When I refused, he started screaming in my room. At the end I gave him RMB200 incl taxi to send him away.
My friend in China told me it is very common trick by smaller agencies. Unless they have webcam, avoid small agencies at all cost.