Issue regrading book search for finding a lowest price of the book throughout internet

Question

Hi all,
         I am currently working on a online book store project and i  had an issue . When  the user searches for a book we have to display lowest price of the book from the internet(means it has to compare with all the book shops in the internet ).And we have to display the prices form the internet  hierarchically in a grid view.A replica of www.addall.com site is what we require.So, please if anybody find any sort of information regrading this concept please reply us back.
        
               Thanks in advance