The purpose of the clamp is to hold the safety retainer to the fuel line so it doesn't get lost during servicing of the car.
There are a couple different ways to proceed from here. Dorman makes a few fuel line repair kits. Hit up Google and check out all the various ones to see if one is best for you. Another method (more costly usually) would be converting your fuel lines over to AN line (braided or not). And the last one may be using rubber fuel injection hosing and an end to replace from behind the strut (where the line is metal) up to the rail.
00 Regal GS: All kinds of cool stuff.