Tracy,
Unfortunately, the Toyota emblem is adhered to the Highlander grille and as a result cannot be simply removed without first removing the radiator grille. To do this, first use a screwdriver to disengage the 4 claws located on the bottom of the grille then remove the clips located on the top of the grille. After that, remove the two clips located on the left and right side of the grille and it should simply pop off.
As far as procuring cheap OEM parts for your Highlander is concerned, I highly recommend checking out toyotapartszone.com, or toyotapartseast.com if you live in the East. They offer the exact same OEM replacement radiator grille that your dealer sells but for $140 as opposed to $189.
www.toyotapartszone.com