Hmm...okay well first of all since you're in the emergency section I'm assuming you have fish in the tank, and since the ammonia is so high it's a pretty good bet that you are no where near cycled.
What kinds of fish do you have in your tank and how many?
Also...what kind of test kit and how old is it? 8 ppm of ammonia is a high enough level to be toxic to both your fish and the bacteria that consumes it.
Next...do you know what your tank water parameters are in comparison to your tap water? I.E. the pH, GH/KH, nitrates etc. This is important because it's perfectly safe to do large water changes to remove the ammonia if your water parameters are similar, but if they are very different you will want to do multiple small water changes over time.