When we were buying our house, we had it inspected for radon, and the numbers were around 25 in the basement. We had a remediation system put in, and everything is fine. We have a radon detector, and have someone come out to check the levels every few years. The levels are now very low --I think below 1.0.
As long as you put in an extraction system, it is no big deal. Many houses in Illinois have high radon levels. They are especially high in basements because the sump pumps pump the gas into your home. Make sure you have your sump well sealed too. It is no surprise that everyone in your subdivision has high radon levels. It is in the ground beneath you, and you all probably have similar soil composition under your houses.
I can't remember what company we hired to do the remediation, but I would never hire them again. They were on the pricier side ($1400), and I thought we would get good service. The people they sent out to do the work were very rude, and they damaged our roof when they put in the extraction pipe. Get at least three quotes, check their references, and when they are finished, inspect their work (especially on the roof) to make sure they didn't cause any damage to your property. Good luck to you!