Create software/add-on for website

I need a postcode search/shop finder that can be linked to a comparison tool or table, similar to laterooms.com. This could either be done using existing software ([login to view URL]) or from scratch, which ever is easier to link to the comparison table. The comparison table should be able to be customised by the site admin for different products and services. For example a site for finding car hire: the user would enter their postcode, the different car hire services would show up and give the basic info e.g. how far away they are. The user could then click compare, it would take them to the table which have all the information that they could filter based off price etc. However all the information could then be changed for a completely different product or service. Ideally i need the software to be able to be integrated into a site using a line of html code similar to many site add-ons that are available.