Try this website:
www.nannyservices.ca
I've gotten a lot of interest from the site - except they all wanted someone with a car - or just didn't know how to read Calgary only..... hehe.
www.CanadianNanny.ca - I haven't had much success with this site, but it has a lot of jobs to offer as well. One annoying thing is it will automatically tell people you need LCP even if you're searching for live-out.
Be upfront about needing a LMO on nanny sites. No use wasting your time or theirs if they won't get the LMO. You can also advertize for nanny jobs on Kijiji. I've had recruitment agencies contact me that way as well as individuals (who all said they would consider a LMO then changed their minds, whatever!). I'm not very experienced as a nanny, however, mostly following that path at the advice of my family.
You could also try searching (google, yahoo) nanny agencies directly.
One more thing... finding a job takes time. Even at my best, it took me three months in the USA where I was allowed to work. Don't despair yet. I'm almost to a year and a half of being jobless in Canada - very annoying but it happens. Maybe it would be good to only job search 1-2 days a week. Designate those the job search days and put it out of your mind (unless you get a call) the other 5-6. Sunday night seems be a hot night for nannying, so refresh your profile Sundays.