Hi Paula,
The best piece of advice is to consult a podiatrist. Since you seem to have a track record of injury, it makes sense to have a proper biomechanical analysis. The podiatrist should also be in a good position to provide advice about which shoes are going to be most suitable for you - what works for someone else may not work for you. Obviously all the major brands make quality cross-trainers with good lateral support, the key is to find the right one for you. I think Ryka and Avia are about the only brands still making a studio shoe as well as cross-trainers. I don't know how many classes per week you are leading, but you probably need to replace your shoes every 6 months or so.
Also, have you thought about strapping your ankle or wearing ankle supports in classes ? I hope you're wearing one (or have your ankle strapped) as part of your recovery.
I used to regularly strain my ankle ligaments running and playing sport; I have used elastic supports for ankles (and knees); and found them beneficial. They provide good compression and support, very helpful for sprains and strains, and lateral ligament injuries. It is like being professionally bandaged, without the bulk. I also find that the ankle feels stronger when I wear the elastic support.
If you purchase an ankle support I recommend the 'figure 8' type (best descriptor I can think of), rather than the anklet type which is just a straight sleeve or sock. The figure 8 types have a seam which runs vertically on the outside of the ankle; and can be reversed to wear on either ankle. They have a heel cut-out of course. Note that there is a possibility that with reduced flexibility in the ankle you may place additional stress on the knee joint in certain movements (twisting and turning at speed) and therefore increase the chance of a knee injury, although I think this is unlikely in BA.
But, for all of that - see a podiatrist first. Good luck.
Good luck.