The only adapters I know of convert a three-prong IEC to a two-prong C7 (or "Figure 8") connector, and not the other way around. You need a power cord that has the two-prong connector on the component end of the cable. If you don't mind using the IEC-to-C7 adapter, you can use any IEC power cord to power your Playstation.
As I mentioned elsewhere in these forums, a friend of mine has an expensive Kimber Select power cord that he used with one of those adapters for powering his Playstation. After auditioning a PS Audio Xstream Power Punch C7 power cord that I loaned to him for a week, he purchased a PS C7 power cord for himself. Apparently, the adapter didn't do that great of a job.