haha I know what you should do!
Go and relpy to her text and say "SURE!" with so much emphasis and emotion to show that you miss her so and your hearts still broken and sh1t, when she replys and says great meet me just say ok see you tonight cutie and remember say "I missed you," with the sincerest voice . When you get there and she is with her friends go up to them and stop abruptly look bewildered but make it obvious and be close so they can ask what's wrong, when they do and she walks up to you say "I'm sorry but I thought you were someone else......I totally forgot about you!" Then say sorry you gotta go but dont leave and call up your pals and just tell them the story right in front of her and her friends about how you came thinking it was the girl you met on SATURDAY and you were going to take advantage of her and say you will meet your friends up to go to a club tonight and have some fun....then hang up turn around and wave and say "BYE" and leave.
HAHAHAHA ohh sh1t that would be awesome....actually I wanna do that to someone now....lol.