Can I sue a car rental company for their renter hitting my parked car

The rental car company and/or the renter are not responsible for paying you enough money to buy a newer car.  Under the law, you are entitled to be compensated for the cost of repairing the vehicle (assuming the cost to repair is less than the value of the vehicle) or the total loss value of the vehicle (assuming the cost to repair is more than the value of the vehicle).  If you are taking care of the property damage through your own personal auto insurance, you should confirm with your auto insurance company that it is going to go after the rental car company and/or the renter to get back not only the money that your auto insurance company had to pay but also any deductible that you were responsible for as a result of making a collision claim with your auto  insurance company.  Depending upon the age of your vehicle and the condition of your vehicle at the time of the accident, you also might be entitled to make a diminished value claim if you can prove through a property damage appraiser that your vehicle has a diminished value as a result of being in a collision.  Good luck with this matter.