Need help picking out lens for my Sony SLR camera to give me crisper pictures?

I'm not a photographer by any means but I would like to purchase a lens to attach to my Sony SLR camera. Most of the pictures I take are of the kids playing or action shots at football games. Any suggestions? I was looking at the Sony VCL-DH1758 Tele Conversion Lens for DSCH1 Digital Camera, Sony VCL-DH1774 74mm 1.7x Tele Conversion lens for Sony DSC-H7/H9/H50 Digital Still Cameras, or the Sony 75-300mm f/4.5-5.6 Compact Super Telephoto Zoom Lens for Sony Alpha Digital SLR Camera. Would any of these do the job?