The waste water pipe from the wall is corroded and broken through. There is about an 1.5 sticking out. It looks like a flange is part of this pipe connection, I need to replace this pipe but I could not budge this with a pipe wrench. Is this a threaded pipe I can change or is this one piece of pipe? The house is more than thirty years old.

A picture would be a big help. I am sure someone could help you out with a picture of your problem.

Because of a lack of details I'm going to take a guess. The pipeand flange in question's chrome correct? If that's so then you should have a short piece of copper pipe that has the chrome trap tail soldered in. If you wish to do the job yourself you will need a torch and some soldering skills. If you have the basic plumbing skills and tools we can help you through replacing the trap. Otherwise it might be time to call in outside help. Your choice! What's your pleasure? Tom