The first step is to get married. If she comes over to Canada she will not be able to bring all her belongings over with her. She is not allowed to move here until PR status has been granted. However, she shouldn't have a problem entering Canada especially with a return ticket.
Then you should file an outland application. Even if your wife/fiance is in Canada with you, you can still file outland. All outland means is the visa office, not your physical position. (I filed outland through London while in Canada, lots of people do)
You will send all paperwork to Mississauga where they will assess you as the sponsor. Then the paperwork will be forwarded to the London office. As you can see from my london spreadsheet, the average length of processing time from sending to mississauga to receiving the passport request from london is 120 days, not 18 months.
Once she gets the PPR, she can send her passport to London from Canada and have it returned to her in canada, she she must 'land', then she is able to obtain a SIN and work etc.
It sounds easy but it is a long and hard process. Join the London thread if you have more questions, people will be happy to help.
So if you want to be together in Canada, you can. I would highly recommend outland though!!
http://www.canadavisa.com/canada-immigration-discussion-board/thread-for-outland-london-uk-applications-t49436.0.html