I ordered and hooked this up for the antenna adapter:
Amazon.com: Scosche NAA2B 2007 Nissan Antenna Adapter: Car Electronics
I also ordered a wire harness adapter so I didn't have to cut up the stock wire harness and did the soldering inside the house:
http://www.amazon.com/gp/product/B00...00_i00_details
*side note: When you solder the remote for the antenna adapter, solder in the blue and white wire (radio booster) with it. This helps with fm radio reception.