They will be more likely to raise your D and B12 levels and keep them there consistently. (B12 injections tend to be "spent" in about 48-72 hours.)

I'd also like to recommend (once again) the Liza Jane spreadsheets, which were developed to list and track almost any kind of test for neurologic symptoms:

www.LizaJane.org

It does sound like you need a new, more extensive work-up, and someone to look at it with fresh eyes.