I'm gonna have to agree with pj7, as much of a jerk I'm gonna sound like, but doesn't your girlfriend have a car of her own that she can drive around? Or are you letting her use your car the majority of the time while you get shafted with the insurance, gas, and repairs? It really doesn't sound fair to me.
As for the bus thing, I would agree with you there. In Orange County, we have a fairly ok bus system, if by ok you mean that it gets you from Point A to Point B. How long it takes to get there is a different matter entirely, of course. I can get to my school in 90 minutes or so by bus. I can get to school 90 minutes or so by bicycle. That's when I decided that the bus was useless for me around here.
By car? It takes about 18 minutes when there is ZERO traffic, 30 minutes on a normal run, and up to 45 minutes in a traffic jam. So I can totally understand about crappy public transportation, dude.
As far as being car-lite is concerned, just look at it this way: how much would you be spending on gas, insurance, and repairs to your cars if you kept driving without replacing any of the errands using your bikes and two feet? I say it's still a good amount of money, looking at it from the perspective of a guy with a paid off, rarely used car and comparing it to the "average" expenditures posted up by AAA.