I agree with everyone else here, she needs to be told in no uncertain terms that she is NOT to come over at that time (or call during dinner, or stay at inconvenient times etc) or she's just not going to get it. I do wonder though, how many other friends does she have? Just from what you've written (and I may have the wrong end of the stick here) you may be the best thing she's got? I'm just wondering why she spends so much time with just you when she's visiting your city, why the only other people mentioned are her mum and DF, and why she'd ask you to be a bridesmaid if you're not that close? Seems to me that maybe you're the only bridesmaid type person she has.

Not that that excuses any of her behaviour, she's being incredibly selfish and needs to be pulled up on it, I'm just wondering if there might be something else there?