emma - cutting someone off is not necessarily the courageous thing to do. It's a very drastic thing to do and the fact that you don't want to because you love her too much despite her failings and how let down by her speaks well of you.
That's why I don't think there's "fat chance" of this getting better. I would assume that any improvements will have to come from you.
Do you think you can reach a place where you are not so upset about things like the event that prompted you to post? I'm not suggesting that will be easy.
A few people have pointed out that if you have a bad relationship with someone, you tend to be more upset by things they do that aren't really all that bad.
But if you could change your mindset from one where you are sad about how your mother doesn't seem to love you, to one where you presume she loves you (she sounds happy to hear from you, remember?) but that she has quite severe limitations in the "showing it" department, how would you behave?
If you weren't full of hurt at her already, you would probably just have thought "oh, she's so forgetful" or "of course, she hates magazines and thinks they're for old ladies" or whatever other way there was of interpreting what she was doing. You wouldn't immediately jump to the conclusion that she didn't care.
Accepting her limitations doesn't mean that the relationship can only ever be rubbish. It just means that it won't ever be the way you want it to be right now. But if you can learn to look at her in a different light then perhaps you will be happier with the kind of relationship that you actually can have with this woman who gave you life and brought you up and somehow left you feeling so sad.