googlemap javascript api pop-up window to provide lat&lon coords to MySQL DB

We have and internal server with the coords of all our delivery (orders). lots of address that are in our orders don't have good match in google geocode API. We wants that someone manually put "lat" and "lon" coords for the address that resolve to "APPROXIMATE" and to "GEOMETRIC_CENTER" in the database so we have a better prediction of time taken to deliver etc... What is required is the Maps JavaScript API code to replace the simple the current html form that ask for lat and long coords. Idealy a new "[login to view URL]" file that would include a function that be called to open a map window centered on the order coords. The user would zoom, move etc to then click on the location...and the lat&lon would be uptaded in the database directly in this function with ajax and [login to view URL] would be updated.. I have uploaded part of the db and sample script on a godaddy account so we can work this out. since our system is behind firewall. the selected freelancer will have access to the godaddy Cpanel account and will have to make this thing works... PM me if you want the url to check it out. Lot of you guys have done it before and googles gives us some hints: [login to view URL] So I don't plan on paying more than 200$USD for this JS function and if you can show me somewhere on the web that you have done it in the pass.. you get the job.