P0430 - Catalyst system efficiency below threshold bank 2.

P0118 - Engine coolant temperature (ECT) circuit high.

What could be giving me these codes. I know there is a leak around the flex pipe on the passenger side. Could that be the reason for P0430? I have only had the car for 10k miles(95k Total miles, 2.8 '01) so would changing the coolant be a possible fix for the P0118?

Also how immediate do I need to fix these?