I registered in one city but then we moved into a new house in another city about 30 min away. Is there a way I can still vote? I've heard that I need to register in the city I live in.

You need to register in the city that you currently live in. If you haven't already, update your address on your driver's license and take that with you as proof of address.

Thanks! Duh. I don't know why I didn't think of that- I almost forgot to do that.

Of course you can still vote! Fill out the National Mail Voter Registration Form to report a change of address. Then print it out, and mail it to:

State Board of Elections
1020 S. Spring Street
Springfield, IL 62704

Here is the link for the form:
http://www.eac.gov/files/voter/nvra_update.pdf

It's as simple as that ;)
Hope this helps!