I don't have the audio box installation disc, is there any way I can get this disc?

You do not need the disc.

You can download your AudioBox drivers from here - http://www.presonus.com/support/downloads/audiobox-usb

To download Studio One, you can login to your account at my.presonus.com and go to "My Products", then "Software". From there you'll see Studio One (assuming you have registered it previously).