I hold a UK ATPL as well as an FAA ATP so I think I have some familiarity with the system(s). The minimum hours required for a UK/JAA/EASA, FAA, Australian & pretty much every other ATPL is 1,500 (with various minima within that 1,500 hours) and requires a skills test. I bet a pound to a penny you *don't* hold an ATPL if you only have 250 hours. A JAA CPL+IR+MCC (with or without passes in the ATPL exams) is not an ATPL, and is not equivalent to an FAA ATP.
Check what's written on your licence.
The minimum hours for a Part 61 (equivalent to the UK's 'self improver/modular' route) FAA Commercial licence is 250 , with various breakdowns within that amount. You shouldn't need 300 hours to get it, just what ever is needed to meet the breakdowns and enough skill to pass a recommendation check for the flight test. Similarly for the Instrument Rating - check what the minimum requirements are then compare them to your log book + enough skill to pass a recommendation and then a check ride.
The instructor rating will require some amount of training (there's a requirement for a certain amount of instruction from an FAA licenced instructor, but it's not much.
The FARs allow for all training done overseas, by an appropriately qualified instructor, to count towards FAA required training. Only instances where a sign-off from an FAA instructor is required has to be given by an FAA instructor.
Last edited by Tinstaafl; 12th Nov 2012 at 16:08.