If they need adjusting there two things you can do;
1) On the inside (side nearest the wheel) of the brake calliper there should be what looks like a circle, with an allen key hole in it. If you get an allen key (5mm I think) and wind it in a little, it'll move the pad closer to the disc, so you'll have to pull the lever less before it bites. Though, make sure you don't wind it too much or you'll get rub, which you don't want.
2) Pull the brake cable through. If you follow the brake cable from the lever, down the frame/forks, there'll be a part of it that doesn't have an outer cable, right where it joins the calliper. At the very end of this, there's the pivot arm that the cable attaches to. You can undo the bolt with an allen key and pull the cable through slightly.
If you need any more help, I'll take some pictures and diagrams
