If you got a working holiday visa for 2012, you activate it by arriving some time in 2012 and after that it is valid for one year. If this is the case and you already activated it when you arrived last summer, why are you wasting your time outside Canada at the moment? You should be using your one year open work permit to work and build relationships with employers. Getting an open work permit is an exception and you should appreciate this opportunity and use it to the fullest if you want to immigrate. Not let it slip through your fingers.
You can find the FAQ for the UK working holiday visa in Canada here: http://www.canadainternational.gc.ca/united_kingdom-royaume_uni/experience_canada_experience/faq.aspx?view=d
You can get another year by applying again for 2013 program. However, there is no automatic immigration you get from this.
If you manage to get a skilled job in Canada and manage to work full time for 2 years, you can apply for your immigration through the Canadian experience class. If you have already wasted some of your first year, you will not be able to do this on your working holiday visa alone, even if you get another year. You could hope they shorten the time you have to work to one year which they are planning to but if they don't or don't do it soon enough for you to apply, you would have to find another way to apply for your immigration.
One way would be to build a strong relationship with an employer so that they would like to keep you and will either apply for an LMO for you so you can get a regular work permit and/or sponsor you for permanent residency through a provincial nominee program.
