Liz, I don't know if you've done this already or not, but you might find, as others have, that if you post your first chapter at the SYW board, potential beta readers can get a better idea about whether they're interested.
For what it's worth, I think you're probably not really looking for a beta read, though. That's when you've got a completed work that's been edited and rewritten until you can't think of a single thing to do to improve it. Since you want input on a WIP (work in progress), you probably want plain old critique and a wee bit of encouragement, like most of us.
Good luck!
Maryn, pleased to meet you