Ask your credit card company to mail you "convenience checks." They look like regular personal checks, but they are connected to your credit card. They allow you to write a check amount up to your cash advance limit.
Ask your bank for your cash advance limit. Everyone has a credit card limit and a cash advance limit that depends on their credit score and other varying factors. You can't write a check that exceeds your cash advance limit.
Fill out a convenience check and write it to yourself. Write in any amount that is under your cash advance limit and deposit it into your checking account at your bank. Wait for the check to clear.
Try to pay back your cash advance plus any accrued fees with your next credit card statement.