She needs a degree, a lot of experience and then to find a company willing to sponsor her. All three need to be in the same field of work.
Also, if she is found to be activily looking for work on a visitors visa then she could be reported to the INS and then no amount of sponsorship will get her back into the US.
Sponsorship is expensive and at the moment only very highly qualified people get into the US via this method. The exception is probably computer people but they still need a lot of experience. If a company is interested, she will need to return to Japan to process the visa. They will generally pay the 3-5k to get her visa and move her to the US.. this has to be paid back if she leaves within 1 year, sometimes 2.