Generally, the principle that is established by Texas State Law is that the at-fault driver’s insurance company is supposed to put you in the same financial standing as you were before the accident. This should mean that you get the full value of your car based on its appraisal before the accident.
However, this isn’t always enough to replace your car. Some insurance companies offer a sell replacement policy which can help cover the difference between your totaled car and your new one, but you will need to check with your insurance company about whether this is an option for your coverage.