First off, go to www.annualcreditreport.com and pull all 3 of your reports and dispute what ever may be wrong or soon to fall off your report due to the age of the delinquency.
Wait the 30 days and then shop around. I would stay away from the big 4 companies or any company that advertises (since you, the customer will be paying for the advertisment). I would also go with an A rated company and no less.
I personally go with AAA. They are an A rated company, but because they don't advertise, your payments will be cheaper from the get go. I'm not sure how insurance brokers work, but I would assume they do not work with A rated companies and/or will stear you in the direction of the company that gives them the biggest payback, not necessarily you.
But, most importantly, always pay your auto insurance on time and all bills on time, the more recent a ding on your report, the more points will be taken away from your score.
Research has shown that people who have bad credit has a tendancy to get into more accidents (could be because their mind is not necessarily on the road, but on their debt). So, that's why insurance companies have the right to look at your report.
Good luck.