This may be the codie in me but maybe she's at her breaking point? Can you get in touch with anyone from any AA that might be willing to go over and just speak with her? It's almost like something in you is telling you to "help her".
The only reason I say this is because it is the childrens mother. I know what she did to you was horrible so I don't suggest you do it but maybe lead someone to her door. Like an angel maybe?? Normally I would never post such a suggestion like that but she sounds in a horrible place and it seems that now would be a good time for someone to show up at her door with love (AA member)
Good luck sweets.