Credit card is basically useless throughout much of China. Purchasing on Taobao is a total pain in the ass. You need to set up an Alipay account and then put money in it via a Chinese bank account. I'm not kidding when I say, buy EVERYTHING you can possibly think of before you leave.

If you find a friend in China with an Alipay/Taobao account, you can just give them cash and they can handle purchasing stuff for you. Would be very helpful to have a contact that can drop ship an important part via Taobao if you break down somewhere and need something sent quickly.