How does an illegal immigrant living in the US for 15 years become a LEGAL resident???
All she needs to do is go get an immagrant lawyer and they will help her set herself up, she has been here to long to adapt to her country again and she has already gotten accustom to living the american way. You say she also went to school here, so she has proven to be a good citizen, as long as she has no bad background she will go thru the same process that anyone goes to, to become legal, she is already americanize and as long as she speaks good english she will go thru the process in two years.