Hi there,
I have experience building highly scalable websites which can handle a lot of traffic, as well as stream videos and photos. I also have experience with various payment gateways, to enable people to purchase memberships to your site. I would recommend dropping the 'webcam' aspect, as that would require a significant increase in the budget, both for creating the website, and for maintaining it.
Please get back to me with some more details, such as, do you have a design built, or do you also need it built? Do you already have the content of the website? etc.
Looking forward to hearing from you,
Ali.