I agree that you will need a new radiator, however, I couldn't help but notice that you said you saw green coolant leaking.
The green stuff is not the recommended MB coolant and may not contain the proper neutral ph balance for your car's cooling system. After you change the coolant, be sure to go with the proper orange MB coolant.
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record