For the ATP written, go to
www.faatest.com and download their software. If you like it, it's $20 to register and has all the faa questions and answers for the ATP exam. You can take the exam at a number of [international] exam chains such as sylvan prometric, etc and I'd be suprised if there was not a place to take the written where you are. Get a medical--there are a number faa approved physicians around the world. A list can be found at
www.faa.gov.
Once you have these, come to the states for the checkride itself.