ways on improving your vocal range?

Question:

Good tips / ways on improving your vocal range?

Yeah...the vocal range. Well, I can say that I have a pretty good voice, and people consider me as a fairly good singer too. That's the problem. I do have a good voice, but has a very limited vocal range. Which means my singing ability is so, so limited. Well, I do practice every morning, when I take a bath, doing a 5 minute warm up while splatting water on my skin (Not a singing activity, just practice warm ups.). I started this warm up about three weeks ago, and I noticed a small effect. I understand that getting a high vocal range doesn't only take a blink of an eye, but I need some tips on how I could effectively improve my vocal range. Please don't answer if you're just planning to screw things up. Thanks! :D

I love the songs on the movie High School Musical...I'm trying my best to sing the best songs in there, though I couldn't reach some notes becoz my range is so limited. If you could also include websites which gives singing tips, please do so. :)

Best Answer - Chosen by Asker: Just keep on doing warm ups and vocal exercises.
You might take voice lessons. Maybe there is a voice teacher at your school. They will be able to help you improve your singing.