starts at the bar, after you sleep she's at the strip club, after you sleep again she will be in the top middle of slums (where the hatch leads and where you can go to the city)
((spoilers) for others - the other cowgirls are one in front of the science building in the city and one in Transylvania before the graveyard gate (after you beat the Manor quest); the bulls are one in the gym and one in the nightclub bathroom in the middle left of the city and one is in the capsule hotel in the underground mall)