hi, whipwan, as I know, for master of accounting, it is really difficult for international students to get financial aids. and the good thing is if you have all the prerequisite courses already taken, most macc programs you can get your master in one year. therefore, although it costs money, it's only one year. besides, with cpa here you can easily find a job in the states though the starting salary is really low (about 30,000$ before tax).
I do think there is much more possibility for you to get ta or ra with PhD degree, but I don't much about the Phd since I've never thought about into the PhD program.