I would suggest you read the forum entry "Car Shipping recommendations" as a start. I plan to ship my car, it is a 2014 model and in very good shape, I expect to have to drive it to NY to drop it off and then fly from there to PR.
Expect to pay around 1,200 for shipping your car but a lot of that will depend on where you live and if you are dropping it off or having someone else drop it off for you. When you get to PR you will need to pay taxes on your car in order to retrieve it, some in the forum have the link to the site to help you determine the tax.
Not knowing how good your Spanish is or your ability to determine a good deal on a car and how well it has been maintained, it is hard to say if you should ship or buy a used car. I would recommend you look into how much you will get for your car in the states and how much time you have to sell the car. Also consider what are you going to do if the car sells long before your moving day.