Well I had a long post typed and my computer decided to delete it
Anyways, I have not read all 5 pages so I apologize if some of my points have already been addressed. I have tons of experience with dogs from rescuing abused/neglected dogs to training. I worked with all breeds but focused mainly on Great Danes.
As it has already been pointed out, dogs will be dogs. Pitbulls are a wonderful breed but in all fairness, they do tend to be more prone to fighting then other breeds. Its just in their brain chemistry but overall, they are a sweet breed. This was 100% your gf's fault why she got bit. You never get in the middle of a dog fight. Best way to break up a fight is water, hose, bucket, etc. Breaking their concentration is key but you don't want to do that with your own body. When they are in that mindset, your hand is just another thing in their way and is bite worthy. Def get the wounds cleaned well and keep them clean. Easily infected and she is going to be very sore for a very long time. The bacteria in their saliva is very powerful and makes the tissues very sore.
Are the dogs in question neutered and spayed? If not, that will help a lot. In my experience once dogs start to fight, they usually do not stop, it only gets worse. I hope this is a hormone issue and once the dog(s) are fixed it won't happen anymore.