clone justanswer.com joomla plug in

Hi, I am looking for a clone Q&A site of [login to view URL] I wish to have the same functionality as this site works well. All payment plug ins, private messenger facilities etc. To see the site just enter a Q (just dont leave a deposit) this will allow you to access the members area to see how the site works and flows. I like the way the site works but I want the user to search for questions and once they find the question from a data base on the site they pay for the answer. Our questions and answers will already be in the database. We will not be researching the questions. I would also like to put the option to download a file or watch a video on the answer page. I would prefer this be a joomla plug in. Only serious offers taken and I will require proof of similar projects that you have undertaken successfully in the past thankyou