Integrate User Accounts

Intro: My website offers a service to bands and musicians where they can upload their album to us, and then we submit it to sites like iTunes for them. What I need: I need to integrate user accounts into my pre-existing website. Once a user is logged into their account they can perform the following task: CREATE A NEW ALBUM: 1. Create their album track/song listing 2. Upload an image for their album cover 3. Upload their mp3's that were listed out in step 1 5. Being able to have multiple albums in their account and be able to view them and make changes to them when they are logged in. 6. Pay the fee via paypal for our service for one or all of their albums in their account. (We charge per album) 7. Once the fee is paid for a particular album, they can no longer edit that album. It becomes closed out so we can then take over and do what they paid us to do.