Rental income or not?

Hi, we live in Ontario, and are renting half of a semi. The basement is a rental unit of it's own. We decided to rent it out. So we pay the landlord the full amount, and then the people who live downstairs pays us for their unit. Now, to complicate things, I run a home daycare in our portion of the home, and last year I claimed part of my rent as a business expense. (Someone else was living in the basement and paying the landlord directly) How will this affect me at income tax time? Do I claim the basement as rental income even though I do not own the house?
Thanks in advance.