How do I change my voice??

I know, pretty stupid question, but, I was wondering if anyone could tell me how to create a heavier, fuller voice when I sing. I have a really high and light voice and it gets to be very irritating at times. I would like to widen my range to do better Alto. I also have a bit of Vibreto in my voice ((it sucks at times. I can barely control it anymore. D;)) so, if anyone could tell me any way to make my voice seem darker and lower, that'd be good, thanks!!How do I change my voice??
it is all about warm up!!! warm ups are key! keep doing them and in time your voice will progress and see where it takes you and stick with it, doing singing thats not your natural style can jepordize your voice and possible ruin your singing plans. learn to work with wat you got.

here check this site out:

http://www.voicelesson.com/html/lessons/



well i hope i was of asistance!How do I change my voice??
well here is the thing to tell you the truth...each person has a unique voice that is ment for them and them alone...so if God wanted you to have the type of voice you have i think you should stick with it but if you really want to try...first try talking in a deep voice then singing i guess
Open your throat a little more , pull those resinaters back and DON'T strain your throat doing it. if you can't reach a pitch you just can't
try using your chest resignator more...