These kinds of vehicles are not good to own in The DR. If you can sell it here, do so and use that money to buy one down there. I've posted quite a bit about this before. Buy only Toyota or Honda while down there and you'll have a much easier time finding parts and such. Buy a vehicle with good ground clearance as there are many "speed bumps" and potholes.
In terms of taxes, they have a table that they use to calculate them, but I don't know what they would be. I will tell you that they are quite a bit (i.e. I just shipped a 2001 Honda Accord and taxes will be close to 200,000 pesos, which is about 6700 USD at current exchange rate).
The only way I would ship this vehicle is if you can get a tax exception (I believe you can bring a vehicle, exempt of taxes, if you're Dominican, have lived outside the country for at least a year, owned the vehicle for at least 6 months, or something to that effect. Not sure about the specific requirements). It looks like you have very little time to make a decision. Like I said before, if it was me I would sell it and use the money to purchase down there.