Chat add-on to classified script

Hi, I got a PHP Classified v7.3 bought from deltascripts.com. I would like to have a chat add-on to it. I already have chat function add-on but i want to change it a bit: Chat add-on requirement as below ------------------------------------------------------------------------- - Online/Offline status on each ad if seller login/out of the classified script. If Online, Visitor can click on Online Status, it will open a Private chat session with the seller. A popup private chat invitation window will appear on seller side for seller to either accept or deny the chat. ---------------------------------------------------------------------- Best Regards, Ryan