The oblivion keyblade is at the hollow bastion keyhole room where you fight riku for the second time. The chest for it should be in front of the 7th princess of heart,cell,thing. If you go in front of the keyhole and turn around then you should see it if you don't know where it is.
For the 2nd question, If you're reffering to the website www.gamestop.com(forgive me if this .is illegal advertising), they do have it in stock. Price about $19.99 Hope that answers your questions.
Sigh, every forum I use turns into a war zone. I kinda miss this place. I might pop in every now and then, but there are so many scars already, I don't feel like I have a home here.
Keyblade Master: AKA Shinaka
April 2005- Feb 2007