CMS Social Networking site

I need to build a social networking site using CMS or anything that easily be managed by myself once the basic site has been installed. I would like something with latest trimmings like vidoe messaging, games,blogs,groups, a twitter link and video streaming. Members should be able to see current members on line, have their own profile page where upload music and photos to their profile page. The site should also incorporate an online shop and secure method of payment. I would also like for the site to be able to stream live music and videos. I have used CMS in the past and found it pretty easy to get to grips with hence why I needs something that user friendly and scalable. I currently have a dedicated waiting to host the site. I currently have joomla and php 5.1 installed on the server. Joomla is OK if you have the time sit and learn it. I need something that is quick and easy to learn. This is a quick small project. I am looking for somebody to either recommend something that consist of what I have sated above or have a working model something that they can install and I can customise it myself with a few pointers. For this part of the project My budget is £50 or nearest offer. Dont let the sum put you off from bidding. There will be added work pertaing to customisation.