It doesn't matter where you get married. If you apply outland, you could have PR in maybe 7 months.
It does not matter if the spouse is PR or citizen except if you and the spouse are not living in Canada. Only a citizen can start a spousal sponsorship from outside Canada. A PR has to be living in Canada when applying for sponsorship of their spouse.
As soon as you are PR and can prove and you have enough income, you can apply to sponsor your mother. After you send in the sponsorship, it takes 27 months to approve sponsorship, see
http://www.cic.gc.ca/english/information/times/canada/process-in.asp#sponsorship and after that it goes to your mothers country and takes another few months, see
http://www.cic.gc.ca/english/information/times/international/08-fc-parents.asp