o2 sensor questions?

Ok got ECU code p0135 bad Sensor heater or something ok so its a bad o2 so my question is where is it located, how do I change it and last since Im poor right now what will having a bad one in there do other than have the annoying check engine light on...in other words do I HAVE TO CHANGE IT RIGHT NOW or can I wait till I get some more cash

thanks guys

well you should notice a sensor on the left hand side of your header if you are looking into the Engine bay from the from of your ride. the other spot would be accessed from under the car on the lower headerportion that connects to the cat...
You can run w/ it messed up but get it replaced as soon as you can.
Hope this helps a bit..

it's on the front of your vehicle, it take about 2 minutes to change costs about 70$. The heater on a 02 sensor is to allow your vehicle to enter closed loop sooner, which allows for less emissions when your vehicle is first started...