I'm old enough to know that the insurance Co. will act in their own best interest and not care about ours.
This is true in any insurance claim, as far as I'm concerned (I have a bias, I freely admit it). It doesn't make it any more or less true because the other driver's insurance carrier is also your insurance carrier.
Your insurance carrier has a "first party" duty to you under YOUR insurance coverage. That is, they have a duty to act in good faith toward you as their insured in claims you make on your own coverage.
The other party's insurance carrier does not have a duty of good faith to you in adjusting claims that you make under someone else's coverage - even if they also carry your insurance coverage.
Accidents involving two insureds of the same carrier happen all the time. The not-at-fault driver generally doesn't get special consideration because of also being an insured. The adjuster handling the claim against the other driver's insurance coverage should not collude with the adjuster handling your first-party claims to "split" the damages or anything like that. Insurance companies are generally very good about following this rule.
If you can't negotiate a settlement that is satisfactory to you, as ecmst12 said, your option is to hire an attorney and sue the other driver. This is where a more concerted effort to make sure that any conflict or percieved conflict doesn't affect the handling of the case. The insurance carrier would hire an attorney to represent the other driver in the suit. If the insurance company has an "in-house" counsel that usually represents insureds, it will instead hire an attorney who is outside counsel (an independent firm) so that the insurance company itself is not defending the claim. This may seem like a minor distinction, but it is actually pretty effective in protecting both you and the other driver from bad faith on the part of the carrier.