How awful for you mrrzy, so sorry. You must have been terrified, but IMO handled it all extremely well. I'm afraid the dog should be put down; as Raggytash and MtheGM say, it could do this again, with even more serious results, even a child mauled. But the poor animal's behaviour is probably the result of bad ownership. Dogs need company and input, routine, exercise and discipline, or they become bored, desperate and vicious. It will now probably lose its life, thanks to ignorant 'dog lovers' who bought it, not knowing the first thing about the needs of these creatures.
Best wishes for a full recovery, you're very brave!