There is no In Canada class for parents. It would have been mailed to CIC Mississauga.
You need to advise CIC of her current address and telephone number so they can contact her if/when they require further information. Leaving Canada will not be a problem. Do you know yet if you have been approved as a sponsor? Check ECAS to see what the status is.
I agree with you that there is no "In-Canada Class" for parents. As you may know there is, however, an H&C where the sponsorship is one of the factors in support of parents' application. Some people would consider this way to sponsor their parents from within Canada on H&C grounds. That's why I asked about Vegreville.
If it was filed via Mississauga CPC, I would call CIC 1-888-242-2100 and ask about the status of this application. As of today, the CIC is processing applications which they received up to January 2007
http://www.cic.gc.ca/english/information/times/canada/process-in.asp