FAA Aircraft Dispatcher Certification
It's not rocket science here, just go to Google search and type in FAA Aircraft Dispatcher Certification Schools.
Finding a school that wants your money is easy. However, getting a Visa to enter the U.S. for training can be hard depending on the passport you have and money will not assist you with that at all.
Since you have so much experience, try applying for "Operations Controller" with your airline and sooner or latter, if you are good, you will become a dispatcher without having to have taken the course.
Good luck!