Questions regarding insurance claim.

Well I had my first accident earlyer tonight. I was on my way to work and stopped in at a gas station. Parked my car over to the side away from any other cars like I normally try to do, to avoid any dings from doors and things like that.
I was about to open my door to get out and I noticed a van was backing up fast coming right towards me, I layed down on my horn and they just kepted right on going and slammed into me. Now I have a huge dent on the driver side between my door and back tire.
Like I said this is my first accident and my first insurance claim. I am suppose to pick up a police report first thing in the morning and contact my insurance provider(NationWide). I am trying to make sure I dont end up getting screwed over on the repairs so I have a few questions that maybe someone can answer that has dealt with this before.
1. Should I be able to get it repaired at a mitsu dealership with OEM parts and paint?
2. Should my whole car be repainted or just what was damaged?
3. Should I take the car and have a estimate done before accepting any offers? If so should I have to pay for this estimate myself?
4. Will I have to pay a deductible if it wasnt my fault? Will my rate go up?
Any tips would be great. Thanks!

You should be able to get your vehicle repaired at the shop of your choice with OEM parts, the dealer included. Most states have laws in place to prevent insurance companies from "steering" customers to certain shops for repair. I live in NY and there are commercials on the radio all the time from bodyshops alerting customers to the law in our state.( It used to be a big problem with many of the larger insurance companies literally telling their customers where to get their repairs done at "approved bodyshops." Many of these shops would install either aftermarket or used bodyparts, and in many instances these aftermarket parts didn't have the proper fit and finish and did not meet the original manufacturer's specifications. I'd call around to some body shops to find out if such a law exists in SC, as I'm not familiar with your state's laws concerning this.
On #2, it may be up to the bodyshop you choose to make that determination. Sometimes they may say only the area that was damaged and repaired, other times they may recommend the whole car be repainted.
On #3, it usually is a good idea to get several estimates for the repair before you submit any to the insurance company.Most bodyshops I know have free estimates, so you shouldn't have to pay for any,especially with the economy the way it is and they are looking for business.
On #4, the best answers may be found from your insurance company as I don't know all of the details of the incident, what the police report states, your policy with the insurance company and any other details that could come into play. Give them a call and inquire.