Customize Joomla Website - Sobi2 and Kunena

Hello, I would like to have some simple customization on my website. My website is developed with Joomla 1.5 with addon components: Kunena 1.6 and Sobi2 latest version. I know some programming but stuck on this area. 1) Do a simple hack on kunena source code: - To display sobi2 listing and info that user submitted on Kunena posts. So each time the user post on Kunena forum, his/her sobi2 listing url will be displayed in the signature area of his/her post. 2) Allow each registered member to submit not more than 1 sobi2 listing Thanks.