Extending vldPersonals dating software functionality (PHP)

I have bought a dating website software from www.vldpersonals.com. The website software is built with PHP. I need to extend the websites functionality, so that certain member types can add other member types to the system, from their own profile, without haing to log out. When a member adds another member, credits should be drawn from that member, based upon how many members the adding member has added. Also, the adding member should get a discount based upon how many members he/she adds.