Why did you buy a Japanese import 147? Wouldn't have thought there was much of a market for that sort of thing.
You should be able to pick up a manual on ebay like this one depending on the year of manufacture.
ALFA ROMEO 147 OWNERS MANUAL--3RD EDITION--DEC 04 ON on eBay, also Alfa Romeo Handbooks, Alfa Romeo, Car Manuals Literature, Cars, Parts Vehicles (end time 30-Mar-08 21:39:55 BST)
Welcome to the forum and let us know what's different about a Japanese one.