Visualising alone is not likely to be enough, that's way too fluffy bunnyish. You and her could do with working together on some serious psychic self defence. Energy body work a.k.a NEW energy ways etc would be a major help here I would have thought. I'm sure you'll get some other solid suggestions. Including if she or you has a strong religious faith of some kind-it's possible you could ask your Deity(s) maybe...not my field however.
If you was UK and close to me I'd offer to help if I could..
If you was UK and close to me I'd offer to help if I could..