i need to know the requirements, the whole process and the average cost !
Best way to get this figured out, is to get in touch with an EASA FTO (flight training organization) who has experience with the conversions of Non-EASA licenses. Check out the links below. But as already mentioned above, you'll have to take all 14 EASA ATP exams and that's the toughest part of the conversion, quite an extensive affair.
Fly Level
Bartolini Air EASA Flight Training Organisation - Fly in Poland
Bournemouth Commercial Flight Training
Profpilot.co.uk: The Cheerful Flight Training Site!
Good luck!