This is sick! 70ccs is just a 20% increase... Also, put it in a glas and see how little it is, totally not worth a surgery. And I don't know what currency 13k is in, but I hope not Euros or USD!
I can't wrap my head around this, your GF isn't a midget or anything, right? I would have said double up to 700 is the minimum, if you guys like bigger boobs that is, if not just wait if she would have needed a revision one day, and then step up, 'cause that is alot of recovering for such a small increase!