Oh my God! That plant puts to shame the ones that I recently saw at regular prices at Lowes. Most of the top growth I saw had dried out due to our extreme drought, killer hot weather, being placed in full sun/windy area and (maybe) poor watering. I would not worry about some dried out leaves; they look to be few. To put things into perspective, the shrubs that I asked someone at Lowes to move had -at least- 3/4 of the top growth leaves already fully browned out.

If you find good prices on shrubs that are hardy for your zone (and you like the blooms) then get them now and plant them as they start to go dormant. Fall is a good time for planting. In the meantime, keep them moist (I add some mulch while potted), place them in a big shaded location that does not get a lot of wind. You will probably not be used to watering them regularly at first so try setting up electronic reminders in Outlook/etc (email software) so you will not forget. The pots -probably- already have fertilizers (those round pellets) so do not fertilize them now. It is too late for that.

The leaves in your photo look to me like they are changing color, which happens normally on most of the Weston PJM group shrubs, such as PJM and Olga, two which are common in the big box stores around here. When I have tried growing big box store Rhododendrons that I have brought in the fall (new shipments, not ones that have sat all season) I have had good success with them.