I think you could get away with the streaks if you wore your hair in a neat or tight ponytail. Then again, take what *I* say with a grain of salt because I seem to be in the minority here regarding how conservative you need to be for a job interview.

Could you go to Goodwill and pick up a pair of pants and a shirt you like? They have some really good stuff for very little money.

Again, though -- my best advice is that if you are cheerful, polite, confident (firm handshake, look people directly in the eye, smile often, listen "actively", ask good questions, and speak articulately), then your makeup, clothes, hair is truly secondary. I wouldn't hesitate to hire someone who wore all black with heavy makeup and streaks in their hair -- as long as they had the skills I needed and seemed enthusiastic, professional, articulate, and motivated. Then again, I was rather 'goth' (although the term wasn't in use at the time) at your age so I am probably less likely to consider goth to be a bad thing than someone who was preppy.