Yes aceytl-l-carnitine can really help with memory problems - I take between 1-2gms a day. It wasnt the only thing that helped at that time, some of it was just increased bile flow/ Liver Cleansing from other things I was doing and drinking a lot of water which dont forget is essential for clearing the head.
Dont forget taurine - take up to 3000gm a day (work up to this). Taking some at bedtime will help you sleep and wake up with a clearer head. It increases bile flow so helps get rid of toxins.
The B12 shots are a great idea and will also help with brain function.
Believe me, my memory and concentration is absolutely appalling at times but it will get better, I assure you.