Okay, then I assume I should wire it directly from the 5v pin on the Arduino board. Thankfully, I didn't brick it because the red light on the RFID board still comes on when I do a digitalWrite.
In any case, the problem is still there.
I think I realized what I'm doing wrong, though. http://forums.parallax.com/showthread.php?129430-Interface-Arduino-to-RFID-Read-Write. On this forum I see that there are codes (e.g. 0x01) for reading and writing. Duh. 
I'll have to do more research.