So I have just seen your other post re asking for asylum you need to focus on what you actually want to do and settle on that approach as getting asylum is a whole different thing that you really need a lawyer to support not a public forum. http://www.canadavisa.com/canada-immigration-discussion-board/tourist-become-illigal-t485516.0.html;msg5936292#msg5936292
See here http://www.cic.gc.ca/ENGLISH/refugees/index.asp
Are your parents still alive in which case do not believe your sister cannot sponsor you, see here http://www.cic.gc.ca/english/immigrate/sponsor/relatives-apply-who.asp
You would need to assess your qualifications, job role to see if you qualify under one of the immigration programs http://www.cic.gc.ca/english/immigrate/eligibility.asp
Failing that you would need to find an employer to sponsor you through an LMIA which are not easy to get as the employer has to pay a fee.
A multiple entry visa just means that you can visit without reapplying each time, how long you can stay each time is never guaranteed and has no effect on applying for PR. The actual process of applying for PR takes a long time and unlikely to be completed during any short visit
