From that.. the heater on your O2 sensor is faulty...
The heater is there to give a reading sooner from a cold start, but once warm it would be fine..
It won't cause much of a problem with your car, and only be wasting a small amount of fuel from cold..
a replacement is the only cure.
there are universal sensors which utilise the existing leads from your old sensor, and can be bought very cheaply.
check http://www.buypartsby.co.uk/lambda_sensors.php
Can someone please confirm it would be the 4 wire sensor that we need..
John