Diagnosed with irregular heartbeat and given coumadin and taken it for two years is that to much?

Nope, not too much, not too long. It sounds like you have atrial fibrillation, which is one cause of an irregular heart beat. The problem with Afib is that it raises your risk of having a stroke or other embolic phenominon by quite a bit, so actually taking blood thinners for life is indicated.
The reason why this happens is that when your atria (which are the two chambers in your heart that recieve blood from your body) are in fibrillation, they're not really beating. Now, they only have to push blood down a few centimeters to the ventricle, and that job is pretty much done by gravity, so that's not really a problem from that point of view. However, it does cause blood to pool there and sit around for a while, and this is a risk for forming a clot.
Once a clot forms, there's a risk that it could break off and go to your brain (causing a stroke) to your coronary arteries (causing a heart attack) or really anyplace else in the body. Obviously, this isn't good, so coumadin is used to prevent clots from forming in the first place.
You take the coumadin for as long as your have the atrial fibrillation, which is often for life.

It depends.

I would ask my doctor about the damaging affects of this drug on your kidneys.

So long as you are getting regular lab work done, and making regular appointments with your doctor to manage your Coumadin levels, you should be okay. Just be aware that by you being on Coumadin, you are supposed to stay away from certain things (certain foods, certain meds). Also before any procedure (medical, dental, optical) you make sure to tell them you're taking coumadin.

Make an appt to speak with your doctor about your PT/INR levels and even ask if he's drawn a PTT recently. These relate to your bleeding time and if they're too high it can be dangerous.

Not if u have chronic atrial fibfillation.