Hello,
well basically you can do whatever you want with the money, as they are not looking for proof that she will return to the US when assessing your PR application.
About wiring money: it can be a bit expensive to wire money and each bank has their own rate, so shop around before doing so as you can potentially save couple thousand dollars (which is nice =)). Look at the percentage they will take as well as the exchange rate! Many people forget that USD and CAD are different currencies and don't pay attention to the exchange rate, big mistake =))
What I am personally doing right now (since i don't know if I will get my PR or what generally will happen next in my life) is the following: I have an account in Russia, and a visa card attached to it, however I don't use my visa as a credit card (as I have money on it ) instead I use it as pretty much a debit, this way, I don't pay anything for taking money from my Russian account, when I buy something using my visa (plus visa exchange rate for CAD/USD is always one of the best, so I don;t loose money that way either). It has to be noted that if you do the same thing, but with a debit, you are still paying transaction fees, plus you are attached to a poopy exchange rate. Another thing is, that when I am taking cash from my visa, I do pay the transaction fee (which will anyway be the case with a foreign debit), thus taking cash should be avoided if possible (poopy rates again). But you can pay with visa everywhere anyway these days, so has not been a problem for me so far.
Wow this was long, but when it is a big sum of money we are talking about, bad transactions can cost you thousands of dollars, so think it through, and shop around =)) And transfer cash only when you are ready to do so, meaning all the paper work is sorted out, as none of us is a fortune teller (unfortunately) =))
Hope this complicated answer helps, Russian Money Loving Raccoon =))