If you want to use TurboTax Online, you can start for Free here: http://turbotax.intuit.ca/personal-tax-software/online-tax-software.jsp
You'll be asked to enter payment at the end of the return in the File section.
If you want to use the CD/Download version, you can purchase it here: http://turbotax.intuit.ca/personal-tax-software/download-tax-software.jsp
