Why would you NEED to buy anything?
Secondly, there are no left side drive Skylines.
Thirdly, assuming you're in the US, which would explain the need to convert it; go read this:
http://www.foreignborn.com/visas_imm/entering_us/7importingyourcar.htm
It'll cost you about 10,000-15000 to import the car. At which point they can inspect it, and tell you no, and then you have the car here, and it will be illegal to drive it.