custody of children

Morning all. I need some advice...any advice regarding my boys. Some of you know my story from days gone by so will know the situation. For everyone else I'll try keep it short.

I have 4 children, I broke up with my violent ex, I moved 300 miles from home with 2 of my sons & the other 2 stayed with their dad. After a very long drawn out custody battle and the involvement of cafcass I got cstody of 2, he got custody of the other 2. The court case & cafcass reports took so long that the judge apologised for the state of the judicial system when giving the final decision.

The Decision was made in January 2011.

I now want to apply for custody of my 9 year old. He doesn't go to school, he doesn't sleep, he cries for me through the night. He basically gets no real love where he is now he just gets materialistic things thrown at him.

I just don't know where to start or what to do. He was texting me at 2 am this morning telling me he was crying for me so bad that his tummy was hurting & he couldn't breath. I've seen him like this before on the days he has to go back home after staying with me.  I had to ring my 15 yr old last night to get him  up & sort my other boy out.  Its heartbreaking to say the very least.

I don't have much money but just need to get this ball rolling asap I just don't know which way to turn.
Thanks for reading