97413 Portal System to Migrate to...

I have a website I want to migrate on to a new Portal System that I want to be able to use for a while. My website has about 5000 people registered and I have a number of functionalitites I want to continue to have, or at least similiar ones for my registered users to have. I also want to be able to either download or at least be able to buy more functionality modules. Like PHP-NUKE which is what I currently use, This Content Management System should allow me create blocks, install new modules, allow users to login, create a new account, add more fields to the create new account, I also would need to embed html code such as embedding Windows Media Player, takes RSS, pictures and videos catalogs, embed You Tube, etc. I also need I also need to assign administration to subordinate admins like me and assign parts of the website. I basically need something a mix of phpnuke, mambo, and maybe typo3, because I need will create subdomains for each site I make. I have a community website where people come and read the news, My site is [login to view URL] I prefer PHP and MySQL mix, but I can be open to reasonable options. Thanks.