Annamaria Gana ,41, is already in jail. Investigators said she shot and killed her 72-year-old husband Antonio Potenciano Gana in their home in May. Authorities said she then shot her 16-year-old son in the arm before her 9-year-old son wrestled the gun from her.
The 9-year-old was not injured.
Prosecutors filed additional charges Tuesday, including a special circumstance of lying in wait.
If convicted, she could get life in prison without parole.
Officials said Antonio Gana was a retired colonel from the Philippines and a former general manager of the Manila International Airport.
Friends said the couple owned a small business in Orange and that Annamaria Ganahad undergone a double mastectomy, chemotherapy and radiation after being diagnosed with breast cancer last fall.