I'd stack the rocks differently to get your anemone higher in the water column if you can't change the bulb. I have an RBTA in an 8-gal biocube (18w PC's) in which one of the bulbs doesn't always turn on the past couple weeks... gotta get that looked at. Criticize me on that one all you want, but the anemone looks great, feeds aggressively, and is overall very healthy, and I've got 5 other, larger, higher lighting tanks to move it to that are already housing RBTA's should its condition begin to worsen. The reason for its well-being, I believe, is that it is so high in the water column that it's tentacles touch the surface of the water when fully extended. IMO, if the anemone is still attached to the rock and is not melting away, it can certainly be brought back. Aside from the bleaching, those pictures don't look too horrible, although you can't see the mouth, and that very well might look bad.
Continue to try to feed it, put it higher so it can photosynthesize, do something about your water clarity (carbon), change some water to ensure good growing conditions, and it just might be on the road to recovery.