You need to shoot at a shutter speed of 1/250 or higher to reduce action blur. Your camera is limited, I believe, to an ISO of 400. It has a reasonably fast 2.8-3.1 lens. What settings have you been using? Have you been shooting wide open at 2.8, at the highest ISO, at shutter speeds of 1/250 - 1/500? What shooting mode are you using - manual, shutter priority, auto...?
Have you looked at the EXIF info on your best shots to see what settings have been working best?
Are you considering the purchase of a more expensive, faster camera/lens combination, or do you need to work within the limits of this camera?
You might find this pro's tips interesting:
http://www.astropix.com/SPORTSPIX/NSC/TIPS06.HTM