Barbara becomes available once Tierra Robada, Bone County and Las Venturas are unlocked.
Michelle is the only girlfriend who is found in an interior.
PREMIUM RACE & TIME TRIAL SCHEDULES A multitude of chances to fatten your virtual wallets and RP, check out the next two weeks of Premium Races and Time Trials: Test your mettle with the Ruiner 2000-locked "Steeplechase" serving as the week's Premium Race and "Del Perro Pier" as the Time Trial.
Premium Races can be launched through the Quick Job App on your in-game phone or via the yellow corona at Legion Square.
I posted a message at GTA Forums asking if anyone had seen C. run into ajealous girlfriend and what could trigger her appearance. I did this till her Stat reached zero, which makes it disappear from the Stats. (You don't read that anyone brags about that one alot on the Gamefaqs message boards.) (At this point, if you try my plan, you might want to wait till the SF savehouses can be bought and have C. Gimp suit dates (Millie) and She Drives dates (Michelle) do not trigger jealous girlfriends.