Event Listener/load node ID

Hi, I have two content types: Event and Venue. I am trying to build a module that allows the address of the event to be auto-populated once the user types in the name of the venue that the event will take place (assuming that the venue is already in my database). The venue of the event is a node reference to the venue name of the venue content type. Once the user begins typing the venue name, if it is already in the database, it will auto complete because it is a node reference. At this point, I want to "listen" for this node that is loaded and copy the street name, city, and state and zip of the venue, and paste it into the event content type form. Any help with this would be greatly appreciated.

Thank you,

Paul