I see. If you need to buy time, she should apply for a visit visa extension showing your funds and your statement that you are paying for her expenses and showing that she has emergency and accident insurance (travel insurance of some sort) and state as a reason that you are going to sponsor her and you need more time to complete and send in your sponsorship application.
There are 3 classes you can sponsor a partner under, that's spouse, common law or conjugal. For spouse, you need to be married, for common law, you need to have lived together in a common law relationship for a year or more and you need to prove that and for conjugal, it is enough that your relationship has been ongoing for a year but there must be some barriers, immigration, legal or otherwise for you to not be able to live together as common law nor to get married but you must have a strong marriage like relationship. It is extremely hard for a straight couple to get accepted under conjugal and double hard for people who are already living together so I would advise not trying that. Rather wait until you have a year of living together and go for common law.
I am not sure which law you are referring to that changed in October. As far as I know, there are no changes at immigration except the one for conditional permanent residency for spouses. That's not a change in definition of partner. It is a change saying that your partner will get a conditional PR for 2 years and after that, they will check if you are still together. This was done to fight marriage fraud. Being married as opposed to being common law will not change anything with immigration except the burden of proof of having lived together for a year before you can apply.