The amount your insurance costs depends on factors like age, type and age of vehicle, driving record, location, approximate driving distance/year, driving record and sometimes profession (as well as others.)
I know that a more expensive car makes your comprehensive and collision more, but shouldn't greatly alter what you'd pay for medical or damage you've done to another's car (unless you've got a huge truck or SUV).
I think that you might benefit from talking to a financial planner (someone not invested in selling you more insurance) who can tell you how much coverage you should plan for. I think that with the cost of medical coverage, even the additional insurance won't cover the cost (you could burn through 100,000 in a surgery and recovery time, fairly easily. If you really hurt someone, say a family, it could blow through the roof.
what kind of car do you have? Are you in the city, and are you under 25? Hve you had more than 1 ticket in the past 2 years or any accidents? That can make your rates go pretty high.