Renault Scenic Exhaust Emissions

Hi folks. i have just had am mot done on my renault megane scenic automatic 1.6 r reg 1997.
the readings are

fAST IDLE SPEAD
CO 0.594 SHOULD BE 0.300
HC 200 SHOULD BE 47
LAMBDA 1.034 SHOULD BE NO HIGHER THAN 1.030

SECOND FAST IDLE TEST
CO 0.607 SHOULD BE 0.300
HC 42 SHOULD BE 200
LAMBDA 1.015 SHOULD BE 1.030

NATURAL IDLE TEST
CO 0.193 SHOULD BE 0.500

AS You can see it failed. any ideas what could be the problem? there is a slight leak on the fron exhaust pipe that needs a plate on which they are fixing, but the garage said that with the readings been so high they dont think this will cure it. They said I may need a new cat convertor but they are not sure. Has anyone got any ideas please? Thanks julie