Urgent - Simple PHP Edit Required

I have a wordpress plug that we have had created, I attach it here.. I basically need the following additon to the script: The plug in is set up to show a pop up on entrance and uses a widget to to place a sign up box in the sidebar. We need to have the option to replicate the pop up on entrance; on exit., This would mean whenever the visitor goes to leave the page, by clicking back button, closing window, typing a new address in the broswer or just moving out the browser window the exit pop will show. **(Note I have attached the exit script so this should be really easy for a good coder to implement this into the plugin)** We need to be able to configure it in the wp-admin section. Configuration is such things as size, headline, colour and content. Hope this is clear, if there is any questions then let me know.