Austen is her maiden name, which she took from her stepfather, Sam Austen. She was raised to think of him as her biological father, and even after she found out Wayne was, she kept the name out of respect. Dodd, as far as we know it, is a name she most recently had, when she was arrested in Harrison, PA. It is believed she had a brief marriage while she had been on the run, but details of this are unknown at this time, because we are missing this flashback.