It's always difficult to say, but ultimately it depends on the strength of your application. They want to see an itinerary of the trip and a plan of where you will go (don't buy flight tickets until you get a visa), that you have sufficient funds to support yourself and pay for the trip and that you have strong ties to your home country that require you to return. Ultimately they want to know you won't be a burden to Canada and that you are going to leave. Don't ask for much more than 2 weeks!
