I wanted to say I'm sorry you and your girlfriend are going through this. I'm unable to answer your questions- I will try to do a little research and see if I can find some more information for you.
Turner's syndrome is caused by an incomplete or missing X chromosome. It is not always fatal. Here is a website with some information that you may find helpful:
http://www.genome.gov/19519119
Obviously, every case is different, but hopefully this information will help. I wish you all the best!
So sorry to hear.I dont know much about turners syndrome, but I did just see a special on TCL about a women who gave birth to a baby girl with this syndrome, so there is hope...