Sit down and make house rules and roommate agreements. Just about every well run home has them. Very helpful. Defines responsibilities, defines who pays what, cleans what, cooks when. That way, when a roommate isn't working out, you deal with it like business. You don't owe her a free place for her and her kids to stay. You just don't. Wanting to help, which you clearly do, does not mean you need to be a pushover victim.
Make a roommate agreement, including a move out date, and require it be respected.
Bu inviting multiple people to live with you in a rental that is supposed to be rented to only one person is setting yourself and everyone else. You likely started resenting it right off the bat.