Caseygina,
First off let me say how sorry I am to hear of your girls diagnosis. I have been in your shoes not once but twice. I lost one in December 2006 to OS and my 2nd was diagnosed in July 2007 and I lost him in October 07. It is the hardest thing in my life I have ever had to go thru and devastated me I miss them both so much.
Bone cancer is very painful, just make sure you stay on top of the pain. Good luck to you and your girl in whatever route you decide to take with her. It is a journey your will never forget.
If you haven't already found it there is a website and support group you may want to check out for bone cancer dogs, the website is
Bone Cancer Dogs.