if you are an us citizen, right now it's best to send in an OUTLAND application. currently, us outland applicants are getting approved in 3-6 months as opposed to the 1.5-2 years it takes for inland approval. Right now May 2014 applicants are being approved!
a person CAN still apply as outland even if they are in canada as a visitor, worker or student, assuming your status has not expired. if you are applying to extend your current stay, it is perfectly acceptable to say you are requesting an extension so you can stay in canada during the processing of your pr application. you would need to submit proof of fees paid for your application, and it would probably be helpful to submit your medical exam too.