How should I proceed if I was attacked in an attempted carjacking that left me unconscious and with a herniated disk in my back, permanent blurring in my eye and a diagnoses of PSTD?

1 The statute of limitations, or time to sue, is two years of the attack any lawsuit must be filed within that period.
2 You would want a personal injury "PI" attorney--someone who sues on behalf of those injured.
3 What the case might be worth is impossible to say in the abstract--it depends on a myriad of factors, such as your out-of-pocket medical costs the extent or severity of the herniated disk, blurred vision, and PTSD, how much they impair dialy life, and their prognosis for recovery whether and to what extent you've lost income or earning potential your age etc. But it's not unreasonable to think that long lasting or permanent injuries like those you describe could be worth several hundred thousand dollars.
HOWEVER, the real issue is, can you recover any money from the attacker? Even if he had some sort of general liability or umbrella insurance policy, it would not cover deliberate criminal acts, and a car jacker most likely does not have such insurance anyway. A car jacker probably does not have much in the way of income or assets, either, especially if he was just released from jail. You might get, for example, a $400,000 judgment but be unable to collect anything, if he has  no meaningful income or assets, since you can only get what he has.
4 What it would cost--typically, when the defendant has money or insurance, these cases are taken on contingency, so the lawyer gets a share of what you recover e.g. 20-33%. But no lawyer will take a case on contingency if the defendant has no money to pay. And if you were to pay an attorney hourly for this case, it could easily cost $10,000, $20,000, $30,000 or more including medical experts...and if the defendant has no money, you'd pay the money for the lawyer and expert and then not get anything in return. 
So this may be a case where you have no meaningful way to get compensation via a lawsuit, unless this is a very unusual carjacker who has money. It's still worthwhile for you to consult with an attorney many will provide a free initial consultation to evaluate a case you can check on that before making the appointment, but you need to be prepared that you may not have good options.