Oh no, she might be disappointed to hear that. But do you think her being a US citizen increases her chances of being approved as a FSW? Given the fact that she is qualified with 5 years work experience?
Go to this link which explains how to immigrate to Canada.
You get the answer under: What are the selection factors
http://www.cic.gc.ca/english/information/applications/guides/EG7TOC.asp