Visitor Discovery and Customer Mapping

My website ([login to view URL]) runs on the Wordpress Theme "BizNaz" and is hosted by StartLogic. I would like to add a feature to my website that allows the visitor to enter their street name, house number and zip code and the feature will locate and map out 5 to 10 of my closest customers to their location on a google map. I would like to capture the information entered into the website form as prospective customers and either saved in a database or instantly emailed to me for action. I can upload my list of customers from QuickBooks Premier Contractor Edition 2013 in the form of an Excel spreadsheet and would like to "sync" this information replacing whatever is currently there with all new data. There may be other API's available from Quickbooks to sync customer data online, that can be made accessible for searching with this feature. I believe I have an SQL database server available to my website from the host. The purpose of this feature is to show the visitor "neighbors" that we have done work for in the past so they may seek them out and use them as a reference. It is my opinion that if one knows someone in their neighborhood, they will strike up a conversation regarding their needs once they know they have something in common. There will be no names or phone numbers provided to the visitor, only address information graphically displayed on a Google map. The timeline for this project is 6/30/2014 for go-live and I would like follow-up support for 90 days afterwards.