So the pads in the rear are wearing faster than the fronts?
On my wife's 2005, she has rear drums...so I assume that the shoes are worn? If so, you need to replace them and make sure that your proportioning valve is adjusted properly. Also, make sure that the shoes are adjusted to the proper setting.
Here is a good article on how to replace brake shoes:
http://www.4x4wire.com/toyota/maintenance/rearbrakes/
(remember to do only one side at a time, leaving the other in tact for reference of how to put everything back together). It helps to have a brake spring tool...needle nose pliers will only get you so far...
BTW, the brake lining is typically called the brake pad.