Children of Addicted Parents and People

Hi my name is Laura, i am 22 years old (i know im not really classed as a child but this has got to a point now where i need to speak to someone) im a shy person who avoids confrontation at all costs.
my mum is an alcoholic, it has only been over the past 3/4 years that i have come to realise this. I suppose it all started when i was growing up, my mum would always have a glass or two when cooking the dinner, i always thought this was normal. then it progressed to a whole box of wine in three days. i knew there was a problem but i didnt want to say anything (what with me hating confrontation), but it all came to a head when i started university and moved away from home, i was visiting for the weekend and sat on my bed, it clinked, so i slid the cupbord open and proceeded to count out 74 empty bottles, i had been gone 3 months and i know they werent there when i left for uni. i finally got up the coutrage to confront her, and she admitted to me (something my stepdad has been trying to get her to do for years) that she was out of control and had been drinking 2 bottles a day, every day. even when she was at work. she worked in a hotel and used to get a water bottle and fill it up from the fridge in the bar at work and swig it while she was sat at her desk. so we asked her why she was doing this to herself and she couldnt give us an answer although i have my suspicions. we got her to go to the doctor and make appointments with the various people, that was in march, she hasnt been to one counselling session, she keeps telling me that shes still on the waiting list or her appointment got cancelled, i dont belive her and i tell her then she cries. i dont know what i can do short of marching her down there myself, she is a very stubborn and proud woman, and doesnt want people to see her as weak. she will often tell me that we come from a long line of strong women and she doesnt want to let them down. so im back from uni again for the christmas holidays and my stepdad calls to me, he has in his hand an empty water bottle that has preciously had vodka in it, i could smell it. this means she has progressed from wine to vodka. he then tells me sha has been down the local shop twice in one week buying vodka, he knows this because he has checked with the shop owner who know us quite well. if she doesnt help herself she is going to lose everything, her marriage is not going to last much longer, my stepdad has already had one afair because of her drinking and i cant see him standing by her if she doesnt do anything. ive tried to intervene so has my stepdad and my grandma, but she just wont listen. i am at the end of my teather, what can i do, i feel so useless.
Laura