I need a backbone when it comes to my children?

I am really ready to move myself out of my house, I am the mother of 4 kids and grandmother to one. 2 of my kids are adults and 2 are under 12, I need advice on how the heck do i get it through these kids heads that i am not their maid, chauffeur, i work 40 hours a week and everyday i have to come home to a pig sty, ive tried not doing things for the older two, such as bring them to movies and what not to see if they get the hint, i just now got done telling my 19 year old daughter if she don't learn to clean up after herself and son then she could find another place to live, and you would have thought i told her to jump off a bridge, when do these kids grow up, her and my oldest son sit home all day, yet when i walk in the door they want to know what im cooking for dinner, i preceded to tell them well you were home all day maybe i should ask you whats for dinner, i want to throw them out and make them take responsibility but i know they have know where to go so i don't see how i could do this. My oldest is getting ready to go into the military, so im sure this with teach him a thing or two, I am just at my wits ends about this the younger two don't do much either so its not just my older two, what can i possible do .