Dear Hollywood, I was quite sad and angry, at the same time, as I read your story.
Sadly, the way I see it, there is no quick fix to the problem. Since you have already made one great sacrifice for your mum and the WTS, the only real option now is to settle back into the congregation and keep up the charade of believing in the Watchtower nonsense while, all the time, looking for a full time job that would enable you to put some money aside while living rent -free with mum. Yep, someone's got to pay for your escape !
Once you've got enough money put away, you can come back here to get some counsel on ways to wake up your mum to TTATT. I would leave it at that for now. You don't want to do anything rash only to be disfellowshipped and then shunned by all who ever knew you ! That is something I believe you're not quite set to deal with at this point.
Keep the courage and do not underestimate the amount of support that you can get on this forum. Since leaving the WTS, I find that this site has become like a new "religion" to me. Lol !
Cheer up young one, you can pull this off nicely!