Nil
Your chances are pretty much nil anywhere since you are European and have an FAA License. With an EASA license you would have been able to build time somewhere like Africa flying bush and then Return to Europe when the time is right. Now that you have an FAA you cant return to EU to fly unless you convert to EASA.
Its best if you went back to the US and get yourself the CFI/CFII/MEI. When you do look for a school (maybe the old school you trained at), try to see if the school is authorized to issue whats called an OPT before joining the school. This OPT allows you to work as an Instructor for that particular flight school ONLY to build time. Yes, you have to complete your training first and it depends on the demands for instructors (this time around is very high).
A lot of people do it this way, and it may be your only way to build flight time so as to work on your ATPL. At the ATP level with over 2000 hours, you may now try for COPA Airlines, Cathay Pacific, Etihad, Qatar and other Airlines that interview low time non-type rated foreign Pilots.
I am offering these tips because my path is almost exactly as I wrote above and it was the only way and the way most people who got licenses in other countries but cant work there.
Think about it, 250 hours is for contracted nationals in Asia, Africa and M.E. Not a national of any of these regions? Welcome to the long road to the Airlines.