I believe this is the cord, likely sold at a Staples store, you can cut off the end not needed and splice to the lamp socket or three prong cord.
http://www.amazon.com/Cablelera-Extension-Power-IEC320-ZWACCDA2-06/dp/B008DW5ZT8/ref=sr_1_26?s=pc&ie=UTF8&qid=1455906476&sr=1-26-spons&keywords=iec320+male+cord&psc=1
Let me know if this helps.