I have purchased Macbook Pro 13 inch, and it was shipped by DHL, but when I received it, the screen was damaged. So, I want to buy a new one. Where I can find it? Because I want to buy and install it.
You should contact the company you bought it from, they should replace the Macbook Pro for you. If for some crazy reason they won't, contact DHL and see if there was insurance on the package, you might be able to get it replaced by them.
I always look on ebay for spare parts. Screens can be found there between $30 & $500, depending on model & housing needs.
iFixIt.com can also be a resource, but I didn't see any screens for MBPs when I looked a minute ago.