I just get a very helpful web site which convert any calendar date from Gregorian to Ethiopia or vice versa or any other calendar.
Hope it will help you.( Don't u think, I help u to save atleast $2 for a phone card to call ur mom ask. when ur birhday was:).....

Link
http://www.funaba.org/en/calendar-conversion.cgi
Example
calendar conversion
from : Gregorian 20010-02-10
will be converted to
[center][/center]to Ethiopian : 2002-06-04 (Yakatit 4, 2002)