What would be a good audition song for me?

The Singer's Musical Theatre Anthology books have MANY choices for audition songs. I would suggest looking through those but make sure you find the books that are labeled for 'mezzos and belters'. Hope that helps!

woo hoo, low altos unite!

Seriously, though, it depends on what kind of song you want to do. If you want a slow ballad, "I don't know how to love him" from Jesus Christ Superstar is great, especially if you are a belter. I personally love "I know things now" from Into the Woods, just because there is so much potential for acting bits in it, but you would have to sing the end where she says "and when everything familiar seemed to disappear forever at the end of the path was granny once again, so we wait in the dark until someone sets us free, and we're brought into the light, and we're back at the start."

its the only part of the song that really shows some awesome range.

I Can hear the Bells from Hairspray is really cute too.

Just some ideas to get you going. You're best bet is to do a google search for "alto broadway songs" and then youtube performances of them, and find one that really clicks with you.

Break a leg!