Hello, I inherited a 2000 Honda Odyssey 3

Hello, I inherited a 2000 Honda Odyssey 3.8 Liter engine and after driving it the engine check light came on. Used a code reader, and here is the information:

P0420 Catalyst Efficiency Below Threshold (Bank 1)

Parameter Description Results
DTC for which Freeze Frame was Stored P0420
Fuel System 1 Status Closed Loop
Fuel System 2 Status Not Supported
Calculated LOAD Value 50.98 %
Engine Coolant Temp 181.40 °F
Short Term Fuel Trim - Bank 1 1.56 %
Long Term Fuel Trim - Bank 1 9.38 %
Intake Manifold Absolute Pressure 15.40 inHg
Engine RPM 2,037.25 rpm
Vehicle Speed Sensor 68.35 mph
Intake Air Temperature 68.00 °F
Absolute Throttle Position 19.22 %

From this information is it possible to tell me if it will require replacing oxygen sensors, catalytic converter or some other fix please, and a shop time and repair cost also please. It is up for a smog check in a month, and i'm hoping to fix it myself since i'm caregiving full time for several terminally ill family members. Any help you could give me is greatly appreciated. Thank you.