Rhonald,
You withdrew money against your MC?!?!? You must have been quite in need as cash advances are just PAINFUL. I told my parents that if they EVER withdraw money against their credit card (any of them), to email me at the first opportunity or to call me to let me know. Otherwise the interest is calculated by the day.
I usually withdraw cash at the nearest ATM...I didn't know they charge $5 now...they used to charge $4... I do agree, don't touch the airports for the ATM, but the Thomas Cook offices aren't bad for converting money.
Don,
Most places in the airport will take canadian or american funds. But outside of the airport, it's best to have local currency. If you can, I'd try to get some RMB (500 or less) just to get you by. As has been mentioned here, you can get a better rate through your lady at any Bank of China (not the other banks there).