I Need a Limited Slip Rear End

So, I just purchased a new 2007 F-250 Crewcab shortbox. I knew it had a regular 3.73 rear axle. There were no choices. So after a few rains, it's obvious. To all of you who think your limited slip is junk... think again. Wait until you don't have it. Then you'll see. I can hardly wait to tow my camper, or drive through the sand dragging my ATV trailer.

So, what are my options? I'm sure the Oval would really dent my pocketbook. Can I buy a gearset to convert it to a limited slip while still using the stock non-limited slip case? What do you think it would cost? Thanks ahead of time.