In addition to changing the footing as much as you can (cleaner stall, stall mats or limestone screenings (which are GREAT as is pea gravel, but if you aren't staying permananty, it's cost prohibitive)) and cutting back on sugars in the diet is helpful, as well.
Since she's having dry hooves in addition to the thrush, you might try a hoof sealer. I'm usually not a fan of these, I feel that the hoof needs to breathe, but too much flucuation in moisture or excess moisture can be detrimintal. Just from below the coronary band (where the periople-a skin substance that grows just below the hairline) to ground level. Don't go all the way up to the hairline! And you don't need to paint the whole sole. AVOID The frog, for sure.
You could try packing the hoof with pine tar after picking the feet out. It's messy, and stinky, but it's a natural anti-thrush. Get some rubber gloves. Its tarry, (it IS named Pine Tar) and smear it in all the crevices in and around the frog. It moisturizes, too. It forms a protective layer, kills thrush and is better for the foot than koppertox for constant use. It's available just about any farm/tack store or catalog.