Looking Chrome Extension Expert for Web Scraping

I need a chrome extension that gathers information from people that sets ads in certain pages. These are pages where the people sell used things or offer services. Please check this sites. [login to view URL], [login to view URL] I needs to go through the ads and get the info from them, name, email, telephone number... I need to be able to specify the category that the extension will explore, and also must not retrieve the info if it has already been extracted(we don't want duplicated data). All this info must go into an excel file.