Create Secure Membership Access/adapt Joomla (repost)

I am creating a scientific site with copyrighted material that has a limited amount of material viewable to the public. The rest of the material would be available to members on a pay per download or view basis. Think of this project as an online course with downloadable or viewable lessons in which registered users only may view pages a limited number of times from a single IP. There must be a provision for becoming a member with unique login and password, acceptance agreement, and modest payment. As it stands now, no provision for payment for downloads exist. This needs to be created using Google Checkout or PayPal or [login to view URL] (and/all or combination of these options.) Assistance protecting copyrights is imperative. Perhaps all the downloadable material needs to be in pdf form with copyright notices and watermark. I am seeking help setting up the registration of authorized users and a digital download mechanism, adapting the existing site and design to Joomla, a little tutoring with wrapping my brain around Joomla since it's new to me (but I use PHPList and ZenCart so PHP is not entirely new.) I have excellent pictures to use in a flash header. The site is very small and simple (so far) but I want to create a structure that allows for growth. This is a repost. I withdrew the project earlier because no one convinced me he or she had a full solution or they suggested using Joomla. I have accepted this advice and installed Joomla. The site is darkfieldstudies.com. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform The site is on [login to view URL]: Latest FreeBSD Unix Apache server