First I'd like to say that I hope your team comes out of the series without a run scored. Secondly, selling tickets for less than face value is not illegal. So go right ahead and sell them on Friday or Saturday or even here. It is Josh Donaldson bobblehead day and tickets on Stubhub are quite a bit more than what you are asking, so you should have no issues moving them at this price.
As for U.S. money, just about everywhere downtown will have an exchange rate posted but my suggestion would be to go to a currency exchange place and get some Canadian money or be prepared for an extra 5 minutes at everywhere while some pimple faced teenager tries to figure out the exchange. Stadium should be fine for U.S. But their rate won't be as good as a bank.