Sorry to hear about the passing of your wife.
Yes, you will need do her final return separately by purchasing a second return. Or if you are using TurboTax CD/Download then you do not need to purchase another return. You can simply start a new return with her information only, since TurboTax Standard CD/download comes with 8 returns.
Here is more information that will help you in completing a deceased return.
https://turbotax.community.intuit.ca/replies/2647725