See the link below to determine how much income you must be making in order to sponsor your parents. The total number of family members must include yourself, your parents, plus any other dependents in Canada (e.g. your wife/husband, your children, etc.).
http://www.cic.gc.ca/english/information/applications/guides/5196E10.asp
You must be making this income when you submit the application and must maintain this level of income while the application is being processed.