If you are Canadian born or gained Canadian citizenship by naturalization, your child is already Canadian. You would have to apply for her citizenship certificate, see http://www.cic.gc.ca/english/citizenship/proof-how.asp
If you gained citizenship because you were born outside Canada to Canadian parents, you would not be able to pass citizenship but you would be able to sponsor your child for PR and then apply for her grant of citizenship once you are living with her in Canada.
Getting a citizenship certificate or sponsoring for PR will in both cases take a few months.
You would have to ask OHIP about coverage. Just make sure you have some kind of accident / emergency insurance for until you get coverage. It can get expensive otherwise.