I always say "Ride what ya got" then see if it works.

Though theft could be a concern, you might spend money now on stuff that you can transfer to a new bike if you find you need or want one. Like good locks, rack, panniers, locking skewers, lights, fenders etc..... I've found that fenders and lights are really the liberators that allow me to bike in any conditions at any time (this is California, we have 2 seasons at best). Before fenders and lights I was constantly looking outside to assess the rain/dark situation and have to adjust my schedule according to it. Now I just watch the weather on the news once a week and see if rain is predicted then put my rain jacket in my bag.

As for the parents and the car...that's a tough one, we commuters have a hard time convincing people that we neither NEED nor WANT a car. You could let them down easy by saying "I'm not sure what kind of car I want yet, I'll shop around once I move". You could also tell them "I dont' really want a car, there's been some break-ins in my apt parking lot" which is pretty much true of any apt complex in every city. Hell, if they insist that you must have a car, say "OK, thanks for the car my dear parents; Can I keep it at your house?"

Sounds like you've got a real kick-ass situation there...enjoy it!