What should I do?? Continue to work far to my kids or go back to my country?

Im a single mom and never been married..I have two kids and i raised them by my self only..In my 1st contract,work for 2years my sister take care of them..but when im nearly finish to my contract..my sister need to go and live in their home which is realy far in my father home.then my step mom take care of them..but shes not realy care for them ..until i finish my 2nd contract..she take care my kids..but i probe that shes not realy care for them as a family when i go back to have vacation..I get them from her and ask my strick auntie to help me to take care of them..now they live separate but both of who take care of them is my auntie's that i knw even they are strick..the concern is there..i dont have savings..but we have our own small house now..if i go back in my country im sure i cannot help them to finish to study ,but if i stay here to work have a big posibility that i can help them to finish their study up to university..what should i do.?