You can not apply as a skilled worker from inside Canada unless you are in Canada on at least a 1 year visa such as work permit or student visa. Otherwise you need to apply in your home country.
You can find this at http://www.cic.gc.ca/english/information/offices/apply-where.asp where it says:
Applicants for Permanent Residence
You must apply in your country of residence, your country of nationality or the country where you have been legally admitted for at least one year.
