Emission Systems And Parts

I have a small window mounted air conditioning unit in my apartment, as it's partially out side it's exposed to the weather but recently it has begun making a clicking and banging sound and alot of water is being blown out of the exhaust. The noise is annoying and it is'nt cooling as well as it has before, i think i've had it for maybe two years now. I've taken out the filter and kept that clean and even drained off some excess water that i found in the bottom of the unit but it's still making this noise. Any ideas on what else i need to do, and is this problem dangerous as well as annoying, or do i just need ear plugs?