I recommend the ToyoDIY site. Once you register and enter your VIN, you can see parts breakdowns of all assemblies, including the suspension. There are exploded parts views, and Toyota part numbers listed:
Toyota lists it as "ARM SUB-ASSY, REAR SUSPENSION".
Part numbers are either 48711-42904 (right hand) and 48712-42904 (left hand) if your car has ABS,
or 48711-42905 (right hand) and 48712-42905 (left hand) if your car doesn't have ABS.
These part numbers apply to my vehicle, but should be identical across the range.
In order to double check them though, it is always helpful to post the specifications (destination market, 2wd/4wd, 3door/5door, manual/automatic, ABS or not, LHD/RHD etc.) of your specific Rav.