All nationalities need to obtain a stat Dec, or letter from the Embassy of their country, USA and soon the UK will need to provide proof of income, I would guess this is through bank statements,
I'm pretty sure this will happen across the board with everyone seeking a non, 0 within Thailand.
The easiest way is to just transfer the funds, if possible use a term deposit account if you don't need to use the cash.
You can apply for a non Iimmigrant b 90 day visa from your own country under the appropriate work category, you can then Come to Thailand and once you have a work permit (normally assisted by an employer as you need to have a contract of employment, you then can extend your stay for 1 year (not a visa it is an extension of your non b 90 day visa) again the school should assist with that.