To make it into the chorus of an actual Broadway show, you need about 6 - 10 years of jazz dance instruction, 4 - 6 of ballet, and about 4 years of tap (unless the show you want to be in is a tap show, in which case you'd be better off with 6 - 7) - or you need to dance with enough skill that it appears that you've had that much instruction. You need to be able to sing at least three octaves. For chorus stuff, acting isn't that big of a deal. For primary roles in musicals, you also need to be able to act well.
If you want to be in a straight play on Broadway, you need to move to a city with a large theatre scene (New York, Chicago, Minneapolis), and work your way up through the theatres there, making a name for yourself and getting ahead by networking well and being able to act really, really, really well. Eventually (if you are incredibly lucky) your reputation will lead you to an agent who has connections strong enough to maybe get you a chance to audition for a broadway play.
If you like to act, I'd say take some classes, audition for the local community/regional theatre, and honestly ask yourself if this is something that you NEED to do with your life.