My fiance is stationed at Fort Knox, Ky. He is PCSing in June to Bamberg, Germany. ?

How soon do we need to get married so I can move with him in June? How long does the processing take? I also have a son (that is not his) that will be going with us so what will I need to do to get him processed as well? Does he need a pport since he is only 7? Will his legal father need to sign off on any paper work? How do we know what we can take with us to Germany and what has to stay in the states in storage? I am in Jersey and won't be relocating to Fort Knox before he PCS so I'm just confused and stressed and need some guidance! Thanks.