A.S.
D.,
We have found fine candidates through Midwest Nannies. They are located is St. Charles, so they specialize in the western suburbs. www.midwestnanny.com
Yes, I believe their placement fee for a nanny is a minimum of $1600.00. You can buy a kind of insurance policy, though. I highly recommend that you contact them.
I had some bad experiences on Sittercity. You really are doing all of the legwork, though it is a good resource for bringing people together. Midwest Nannies does this work for you.
You can also purchase a manual from them. For @$36.00, they will show you how to go about finding a nanny on your own.
Good luck.
Amy