your mom can stay in Canada as a temporary resident for as long as CBSA officer approved it at the time of entry into Canada (usually 6 months at a time, after that it can be extended). After Case Processing Centre in Mississauga sends you a letter informing you that you can sponsor your mom all the documents will have to be sent to the visa office in the country where your mother normally resides. She may be asked to attend the interview there however she can complete medical exam in Canada, she can find a CIC approved doctor here: http://www.cic.gc.ca/dmp-md/medical.aspx
If interview is not required she may be able to stay in Canada while your/her application is being processed. She can even get PR status (land) at CIC office in Canada.
Instruction for the sponsor (you): http://www.cic.gc.ca/english/informatio ... family.asp
Instructions and forms for your mom: http://www.cic.gc.ca/english/informatio ... famcls.asp
Your mom should also read instructions specific for the visa office in her country of residence.
hope this helps.
Regulated Canadian Immigration Consultant (ICCRC # R408031)http://www.immconsultant.com