we need web scrapping with social networking site

We need web scraping with social networking sites for one of client same as http://www.socialreport.com/ and http://www.brandwatch.com/ doing/providing services to get all data(wall, post, images etc.) from social networking site.
Please suggest how can we achieve this with Face Book some permission/dlls/Plug-in we need to purchase?? and how will proceed for the same to get it done.
We are using Microsoft .net environment for our application/website.