Just because she is not good with other dogs does not mean she will not be good around the baby.
How old is the dog? Has she been spayed? Do you know the breeder that bred her in the first place? If so it may be an idea to have a chat with them.
Where does she sleep at night? If she is sleeping in your bedroom now would be a good time to get her used to sleeping in the kitchen or somewhere else away from you.
Crate training is also a good idea, then when the baby arrives you have somewhere the dog can go that is solely the dogs space - her 'den' if you like.
You could well struggle to rehome her in the present climate, to a good home anyway. Sadly the rescues are already full to breaking point with Staffies.
This is a good article to read about introducing a baby to a house with dogs:
http://tripp.fenderson.net/friends/karenoveral l/protocol.html