Should I copyright in the U.S. or my own country

Hi all. I have a website idea that I would like to copyright but don't know where to go to do this. Should I file for copyright at the U.S. copyright office even though I do not live in the U.S. or should I file it in my own country?

If I file it in my own country, but someone in the U.S. infringes on it, am I still able to take legal action?

 

This might have some answers, sorry didn't read through it all - http://www.copyright.gov/circs/circ38a.pdf

 

Thanks. That helped a little. Seems like the WTO plays some sort of role in enforcing the copyright internationally. Or at least that's what I think they are trying to say.