I can't tell what 4Runner you have but if you have a Sport or Limited they won't fit because I believe that they are 16" and you have to go with 17" for the models above.
But you could find them at any Toyota parts department or at partznet.com.
The dealers have TRD catalogues (as well as displays) for 2007, just looked at one last week, they have those wheels in the catalogues if I am not mistaken. They are 16s, but I do not think that would make a diff.
typical option for a sr5 is 17" wheels...so check your size. in my region, the upgrade to 17" wheels was $80...so practical every vehicle the dealers ordered had this option