Air con system don,t have radiators,they have condensers.Most manufactures use a dye in the 134a gas so if you do have a leek it,s easy to spot.

New radiator = £130
new condenser =£150
Air-con regas =£50

Condensor is in front of the radiator.
The cooling fins (ziz zag type paper )can work loose and hang down but as long as the cooling ducts are not damaged it should be fine.