Whenever we get a student in from the Paid Professional Program, we always give them the same advice for improving their English before their internship starts. Here it is: 1. If you're sharing an apartment with people from your own country - move out. You can find plenty of cheap apartments to share with Canadians here: http://vancouver.en.craigslist.ca/roo/
2. Volunteer on the weekends. You don't need to do it every day, just once in a while. Volunteering will help improve your English and improve your resume. You will be of course speaking with Canadians during your volunteer period, but you will also be adding Canadian experience to your resume and showing future internship hosts that you are familiar with Canadian working styles. You can find lots of volunteer opportunities here: www.govolunteer.ca
3. Join a club, get out there and meet Canadians. It's a lot easier than you think. There's a website called MeetUp.com . That website organizes thousands and thousands of free to join clubs where you can find people who share the same interests as you and you can join their club. Each club has regular 'meet ups' - those are events where everyone from the club gets together to do an activity.
Don't join, language exchange, or international student clubs though - that is what you're already getting at school. Instead try hiking, or sailing, or running, or reading, or photography clubs. Anything where you will share your interest primarily with Canadians. It's very active and there are lots and lots of choices - in fact just tonight when I'm writing this, there are more than 40 different meet-up activities you could participate in.