I recently switched from an AuPair to a senior in HS doing aftercare for my kids. In order to get ANY response and reliability, i pay $25/hr.

If you are not getting responses, then you are not offering an appealing package.

If a college kid would be all right with you, try advertising near the community colleges. I have found that those kids need the money, rather than kids at the 4-yr schools who are working on the side for "fun" money so you might find more applicants.

Find someone who has a morning job or an older person who wants part time hours. Young college kids won't be reliable as their schedules change

Maybe you and this poster are a match made in heaven: http://www.dcurbanmom.com/nanny-forum/posts/list/333972.page

DC is going to start preschool this fall and at first, we'll need afternoon care (2:30 - 6:30 p.m., give or take) on a daily basis, then drop down to Tuesday/Thursday on the same schedule, maybe in January. It's fine if it's two caregivers, a MWF one (who will be temporary) and a Tues/Thurs one who will be ongoing. I recently advertised on Care.com for a similar need, i.e., caregiver with afternoon availability, albeit kind of last minute and a temp gig of just a few weeks, but I hardly got any responses. It makes me worried I won't be able to find anyone this fall. I've heard from other mom friends how hard it is to find someone to do afternoon pick-up and I wonder if it's the same with an afternoon sitter. I think a college student would be perfect for DC, i.e., someone young and fun, but it seems like their afternoons are filled with class.