Those prices are insane. We really do get reamed over here on parts. People say you should support your local industry, but how can we?
Rotating groups for a pump, i was quoted 2,600 per group, i bought them for 400 each. That was a retail shop in america, Bobcat would be buying them direct from the manufacturer, go figure.
With the exhaust gas in the radiator, it has to be the EGR.... I assume its such a small leak you can't use compressed air to see if there are any bubbles on the coolant side?