... Calm down, kid.
I get your issues with her. I probably wouldn't love waking up to see a message about gangbangs on her Facebook either... even if I knew it was a joke.
As for the new years thing - It's a promo for a new years party. Do you think if they plugged it as "a boring party full of girls who already have boyfriends" that they'd get a lot of interest?
My advice here is simple:
THIS IS YOUR GIRLFRIEND OF FOUR YEARS.
You are in a relationship with her (Long distance or not). This isn't pickup anymore. This is your girlfriend.
Communicate. Like adults. Talk, on the phone or in person, or messaging or anything, but talk about your issues if you're having issues.
She won't know you don't like the shit she's doing if you don't tell her you don't like the shit she's doing and why...
If that fails, THEN you consider other options... (That is if you love her and want to make it work - otherwise, yes, onto the next, of course...)