Are you already doing PPC? This is a really good practice area for PPC. If you’re not doing it, you should be.
You can also expect SEO for Criminal cases to be on the high side, especially in a city the size of Toronto. Avoid anyone willing to do it on the cheap, you can do more damage than good if you get the wrong guy.
You would likely have better results with a referral from a firm with a different practice area. Tax law, family law, and DUI are very good SEO targets, ask lawyers/firms you trust in those areas for a referral.