What gear do I need to start my own Photography Studio?

I need some help, what equipment do I need to start a photography studio. I'd like to make a list of all the equipment and see how much I would spend. So far, I have a Nikon D7000, 2 interchangeable lenses. And then a 12 ft Muslin backdrop and stands to hold it up.

Well these are my suggestions. I don't know if its what you looking for because i'm only a 13 year old amateur photographer and you didn't say what kind of photography you were doing.
These all pick up on eBay quite cheap!
Soft boxes
Umbrella
Constant Flash
Backdrop
Tripod
Photoshop on a computer
A USB lead so you can do tethered photography (plug it in laptop and camera at the same time and as soon as you take a photo it loads onto your laptop)

Hope this helps!