You need some book and can't find it in a library, it is better to buy online.
The Chinese Amazon is called Dangdang: http://www.dangdang.com/
You can find all the books you need.
However this website is in Chinese. You can always use some automatic translator to look for some book.
As for payment it is a little complex: you should transfer the payment from a bank account. In China you need to check with your bank to pay online. It is better to open a specific bank account used only for online payment. Also after you pay you will receive some number on your mobile phone for security reason.