G.♣.
I'm actually very surprised that so many people have suggested that you speak with the principal or superintendent. Chances are, they won't have a clue what you need to do. They don't analyze college transcripts when they interview candidates. They simply ask to see your teaching certificate. They don't usually know what the requirements are.
You need to get a teaching certificate. Unless your state specifically says you must have Master's Degree in order to teach (Illinois does not), then right now is not the time to focus on earning a degree. Now is the time to figure out what classes you need to take to get a certificate.
I earned my bachelor's degree and then went back to get my teaching certificate. I met with an advisor who looked through my transcripts and made a note of each class I had taken that fulfilled a requirement. Then he made a list of the classes I still needed to take. My degree is in Math. I needed some math classes that my degree did not require, I needed education classes (since I hadn't taken any originally) and I needed to pick up a government class and a biology class (I think). Some of the classes might seem random, but states are funny that way. You're also going to need to student teach, and that's usually the only thing you do that semester.
Call the education department at a university (UW would be a good place to start) and ask to talk to someone about what it would take to be certified. After you have a job, you can consider a Master's Degree. Many schools have on-line classes. Just because UW is a residential school does not mean it doesn't offer plenty of on-line classes. But first, find out which classes you need to take.