I think he's more interested in being quick than tips on fighting
Bump to what kangaeru said. You need to lose weight. You won't lose weight doing sprints. I recommend doing long distance work first. Once you lose some weight, that's when you can start building up your speed.
Another thing to point out is that you don't want to just improve your quickness. You also need to be able to MAINTAIN that speed. Basketball isn't over in 10 seconds like the 100 metre dash. Doesn't matter how fast you are if you can't keep it up over the course of the game. Make sure you balance your speed with endurance.