Relationship stuff, help lol?

So I am throwing a "mini-prom" type thing for my gf because her prom this year sucked, she took a guy that she was just friends with, she paid for everything, the limo, the tux, her dress, the whole nine yards, then as soon as her and her date got to prom he bailed and chased after this girl he had a crush on. Anyways, I was supposed to have a dj there but he ended up finding a jig that offered more pay so he bailed, even after I offered to increase what I'd pay him, so how should I go about this, the dance is Friday!! Help???