
My Mastiff pup was a bit like this. At first he refused to leave the house for a walk, after a couple of weeks of getting him confident enough to approach the front door he finally went thorugh it, only to lay down on the front lawn and refuse to move any further :(
He did overcome his fears and now loves his walks :)
It's a matter of being patient. Try to encourage your pup but don't force her as it will only make her more frightened.
I used treats to reward any positive movement in the right direction. I also would take pup out on the front lawn for 15 mins (a few times every day) and just let him lay down & take in all the sights and sounds. before long curiosity overtook and he wanted to go and explore the big wide world.
I think it's worth taking your pup outside for a walk but get her to sit down for a few minutes (close to home, ie outside your door) and then taking her strait back inside. When she appears to be comfortable with this, take her a little way further before you get her to sit. She should get the message that she will be able to go back home and that she isn't going to be stuck in the scary street forever. It also means that she will associate going out with a positive (coming back inside to familiar surroundings). She will get over her fears and then the 'positive' will be the actual walk itself.
You can do the same with the car. Drive to a spot, get pup out, but dont' go away from the car, just sit & take in the scenery for a little while. When she is comfortable with this, move away from the car etc...
You should find that as she starts to feel confident outside then there will be no stopping her :)
While pup is sitting/laying taking in the sights, reward and positive behavior, such as curiosity, but be very carefull not to reward any fearfull beahviour - just ignore it.
My pup decided in the end that walks were so much fun he didn't want to go back inside & would chuck himself on the lawn so he could stay out longer!