Your radiator is probably the aluminum core type with crimped on plastic side tanks. A common failure mode is for a leak to develop at the crimp joint. As a quicky fix you could try some Bar's Leak pellets available from most auto parts stores.

There are some outfits that can repair the radiator by replacing the side tanks, but some say the repair is not that reliable.

The radiator is made by Behr and is available through aftermarket sources. The price through the aftermarket is probably cheaper than the same radiator through the dealer. The only difference is that the Behr radiator through the aftermarket may not have a MBZ part number on it.

Duke