S.
(hugs)
Since you have already spoken to your mom and set the ground rules, you are probably going to have to step on toes and create some hostility. :-(
My FIRST suggestion would be to talk to someone in your church and find local programs that provide shelter to seniors with little or no means of supporting themselves. It will be EXTREMELY difficult, but unless your mother will follow the rules in YOUR home (like you had to growing up in hers)... you will not regain authority in your home. Your mother is being selfish and most likely feels that she knows what's best, not looking at what she is truly doing to you and your family.
You and your husband are amazing to be in the position to take your mother in. Your mom is taking full advantage of you... and until there is the real possiblity that you will put her out, she will not change... and even then it will probably get worse (sorry, to say something so harsh)... but if she can't follow your rules, she will probably start telling you 19 month old things (they really do understand a lot)... as you notice she goes to her first...
Another suggestion would be family counceling... FORCING her to go with you...
(hugs)
*edit* -- Although I love my parents... if I were in a position that I did not feel respected, I would not continue the relationship with my parent(s). Actually, I had a very strained relationship with my dad after he remarried (IMO the wrong person)... but after a few years, it improved... but it took time. That said, I would find your mom a place to live and then tell her about her new place... and "this" is your move in date.
Good luck!