Oh no! I wondered for a minute when look at the pictures why the taco bell sauce and cigarette butts. Makes sense now. XD
I'm sure you'll win the dog at large fight. If you have any nice neighbors/friends that saw her in your yard only, I'd call them up to testify to the fact that she never left.
I had a roommate once leave the house and leave the front door wide open. Frag walked out... he was gone for an hour or two.
Finally came back, thank GOD.
Good luck! At least she's cute.