Unburned fuel will wipe out your cats. You need to have that problem fixed ASAP and hope you cats are still ok. Changining a fuel filter will not help with a too rich code. Your upstream (before the cat's) 02 sensor read the oxygen in the exhaust gas and tell the computer to adjust accordingly. The downstream 02 sensors (after the cats, aka catalyst efficency monitors) monitor the exhaust gas after it passes through the cat's. In your case I'm assuming they are indicating too much unburned fuel. If you have both codes indicating both banks are running rich you either have multiple cyclinders missing on different banks or I would guess you have a fuel pressure problem (too high) that is causing your car to run rich. If you can access a fuel pressure gauge, that would be the first thing to check.
