Relocation to Chicago and the cost of living

Hi everyone,

I am French married to an English man and we are currently living in London. His company has offered him a job that would mean we have to relocate to Chicago around October time this year. We are plannning to look around Downers Grove, Oakbrook where my husband offices are based.

We are at the negotiation stage and unfortunately after being stung way too often the company no longer offers relocation packages so we are trying to get some costs approved as well as the salary.

In order to do so I would like to have a realistic idea of the cost of living for a family of 4 and I would be very grateful if someone could let me know what to expect on average each month for the following:
=> Electricity/Gas/Water
=> Food bill
=> is there a good place to get quotes for health, home, pet and car insurance?
=> Is there any taxes the equivalent of the council tax here?
=> Is the income tax taken before the wage is paid or do you have to declare and pay independently?
=> Is there anything I am not covering here that is important to consider?

Many thanks in advance I really appreciate the time anyone will take to answer, it will be very helpful! :)

Peggy