How would you do this halloween costume...?

I want to be Lady Gaga! LOLz So my friends that work with me for trunk or treat with our church this year have decided a music thing. One of thems gonna be Hayley from Paramore and the other idk my dads gonna be Elton John and Im going to be Lady Gaga!!! Where could I but the stuff for her outfit? Which outfit should I try to copy? It has to have pants since it is a church thing :P ALL GOOD LINKS WELCOME!!!