where to buy a Swirl Control Valve Control Position Sensor?

Question

I have codes p1137 and p1138 on my 2003 nissan sentra 1.8L. I guess these two codes are the same. I am planning to buy a new Swirl Control Valve Control Position Sensor to solve the problem.  I can't find it in any auto parts stores next to me also, I couldn't find it on the Nissan website to purchase one. Can you help me where can I buy one? or can you give me some keywords to look for the sensor?

Also, I did follow the diagram provided to locate the sensor, but I am not sure if this the right one, so can you please send me a real picture of a 2003 nissan sentra 1.8L . Sorry, but I have a hard time reading diagrams.
Thanks, I appreciate it!