Ok so just to clarify... You are American and she is Canadian?
Unfortunately they are very sticky at immigrations, especially when you have an application for permanent residency in the processes. (The majority of people I have seen have all been denied entry into Canada if they had a PR in the process too).
Do you meet ALL the requirements for conjugal partner? Check out requirements at:
http://www.cic.gc.ca/english/immigrate/sponsor/spouse-apply-who.asp#conjugalIf not, why not get married? I am not sure how immigration is in the USA but if you are trying to immigrate to Canada there is no income requirement to sponsor a spouse. I am not too sure about also includes conjugal partner but am absolutely certain that theres no min-income for spousal. (I'm in the process of things right now). Also, my friend who has already sponsored her husband a few years ago, had a very low income of 8000 for the income form (it asks you how much income you have made for the past year) and they were still approved.
Hope this helps a bit...