Knee pains: Where can I get a good brace?

[AdDiEkRiStEn]

I'm 15 and I have terrible knee pains. I had tendinitis in it but now it gets to where it hurts above my knee cap also... This has summer I strained my acl. I'm constantly pounding on it because I'm a cheerleader for two hard core squads. I also teach a gymnastics class and I'm assistant coach for a competitive cheer squad. Getting up and down from spotting the little kids kills it. Sadly, I'm going to need a brace as much as I don't want one. What kind do I need and where do I get those? Please send pictures or links