My mum's an alcoholic, what can I do?

At this stage all I can think of is calling the police or getting her sectioned :( She's been an alcoholic for over 10 years now and it's getting to me by this stage (I'm 20 so an adult so I can look at it a bit more rationally). All that happens is arguments between my dad and her who obviously loves her or he#d have taken more drastic action by now. She just drinks from dawn till dusk and does nothing except steal money from all of us to go out and get more. I'm just afraid that doing either of those 2 will destroy my life further and tear my family to shreds :( Does anyone have any advice?