Hi, I am a doula (no longer practicing) and I used doulas for both of my births. I really enjoyed having extra support for myself and also for my husband. I liked having the presence of a calming woman in the room with me...even though I also had awesome midwives. It was nice to have someone who wasn't also responsible for my medical care there. She could get my husband food. She could pray for me, give me a massage when my midwife had to step out or check my blood pressure, etc. She was also with me during earlier labor before my midwife was there and was able to give me suggestions and support. She also took photos for us so that my husband could be 100% present for me during the birth and made a few phone calls too.
You should find someone you feel comfortable around. Interview a few doulas at least so you can get a feel for who you might connect with.
You can go to www.birthlink.com to find doulas in the Chicagoland area. Or go to www.dona.org and run a search for Naperville.
Here are some suggestions from Dona.org about interviewing your doulas
...http://www.dona.org/mothers/how_to_hire_a_doula.php
Hope that helps. Blessings on your birth!
H. M.