Dog for Girlfriend

Hey everyone,

I need some advice. I would like to get my girlfriend a dog for her place as an early christmas present. She lives alone and is going to school and I would like to get her a dog that will keep her company as well as protect her if something was ever to happen.
She is good with dogs and loves boxers. And we both like labs and german shepards.
Which dog would be a good choice for her situation?
Also, where should I look for finding a quality pup?

Thx.