Sorry to hear that your girl is having trouble! B-complex vitamins sure can't hurt if she has any nervous system damage. If you have trouble getting her to eat the broken up B-vitamins, you can try nutritional yeast. Look for a brand that is very high in Thiamine, for your specific problem.
E deficiency can also cause the symptoms you are seeing, but you must be careful not to overdose E, as it is fat soluble, and can build up in her system and cause other problems.
Here's some more reading:
http://www.merckmanuals.com/vet/pou..._poultry/vitamin_deficiencies_in_poultry.html
Is there any chance she got into some lead? This could be a single lead bb from gun ammunition, or some old lead paint flakes, or .. well, heck there was LOTS of stuff made with lead back in the day and a lot of it got left laying around old farms. Even a very small amount of ingested lead can cause leg problems like this.
Has she been like this long, or is it sudden? If sudden, has she had access to any wet areas where water has been stagnant, or where there might be any animal carcasses? Not to sound grotesque, but if so, botulism might be an issue.
Double check that your feed is very fresh and that there is no chance it got damp or moldy. What are you feeding exactly? Aspergillosis, caused by aflatoxins in feed, can cause these symptoms.
Otherwise, there are some diseases that can cause lameness and leg problems. Do you have any history of any other symptoms in her or any of your other birds? Have you added anyone new within the last several months?