How should I figure my settlement for injuries resulting from a car accident?

There is no magic formula that determines how much your claim is worth.  Generally, you want to first make sure that the tort feasor's insurance carrier pays for all of your medical bills.  This way, you are not having to use any pain/suffering compensation to reimburse the medical providers for their services.  Secondly, you need to make sure that a doctor provides you with a permanency rating.  this is a percent disability rating that helps determine pain and suffering as well as future pain and suffering - indeed, you want to know if you will need any future surgeries and take the costs into account.  I am not sure you have such a rating yet and I would strongly suggest asking your doctor to give you a permanency rating as well as a estimated cost of medical expenses. the 40K figure sounds reasonably, but you cannot say that is reasonable for sure without a permanency rating.