What web program is required to upload audio and video and more?

I have a website that I built and manage for my brother. It is located at ...
secularbull.com

I want to have TWO kinds of options in respect to the site. I want people to be able to browse the site no matter what, without having to signup with usernames and passwords.

Then I also want people to be able to input usernames and passwords so they can create an account, and upload their firms logo, their news releases, including audio and video capabilities as well. File uploads using some of the following extensions such as, .jpg, .gif , .wmv, .mpg, .wma, .mp3, would also be an asset.

I would like them to be able to update their accounts as well.

Any suggestions as to what program I should be looking for? How much it may cost, and where I can get it from???

Thanks a bunch... I always appreciate the responses I get!