Even if you can't find the sets you want at a TRU near you, also try Tuesday Morning, TJMaxx, and Marshall's in the near future - they often get the clearance stuff a little later so you might have some luck, especially this fall once the stores start setting up for the Christmas holiday. Also, if it's not too much of a pain, keep checking at TRU as there may be some sets that are returned.
Toys R Us
are the clearences in certain fixed period or periods of the year?