Just curious how an '05 is out of warranty already. Should be covered for at least 3 years. Typical things that are not covered in waranty are items that wear out, or need regular maintenance (ie. brake pads, wipers, shocks/struts, oil changes...) The sending unit is something that should be covered.
Have you checked with the dealer to see if it's covered?
I know it's a "little" out of your area, but you should stop by Norwood Chevrolet, and ask them about it.