From a financial perspective, it's almost always a smarter choice to drive an old car that's paid for than to buy a new car requiring an auto loan.
While your old car is getting up there in miles and age, it doesn't really sound like it's requiring a lot of repairs. In reality, you are spending the majority of your dollars (at least what you cited in your question) on maintenance, and that's a big difference.
Maintenance, which includes regularly scheduled work when your car reaches a certain mileage as well as wear-and-tear items -- such as tires, brakes and windshield wipers -- are costs all car owners incur, regardless of the age of the car. These costs don't disappear with a new car -- unless you buy a model with a free car maintenance plan, and then they may only be free for a limited time.
Even with an inexpensive car and an auto loan at a great interest rate, you are looking at a minimum of about $2,400 annually on car payments alone. It's unlikely your older car will cost you $2,400 in repairs. Either way, you'll likely be paying for maintenance.
Instead, don't let the costs of necessary car maintenance on your used car sneak up on you. Put aside some money each month into a car fund, similar to the way you would if you were making a monthly payment on a car loan. Use the money from that fund for your current car when necessary. If you plan it well, you'll have more money in the fund than you need, which you can use for a down payment when you decide to buy a new car.