Im bi how do i get this girl to me mine.. im a girl?

this girl shes gay she liked me and she ask me to be her girlfriend but at the time i wasnt ready to move into to being biual.. and week later she with this girl and she and her start goin out. me and the girl that ust to like me we go into a fight and i called her a fag. we almost go physical... and now she supper serious with this other girl.. and every week her and the girl break uo and get back together i told girl how i felt about her but she saud she wanted the other.. i like her so much and i want her so bad.. and there this banquet comin up and i want her to be my date how do i break the two up and make her mine... please help