Did you try the local paper? www.mcall.com then classifieds, jobs. They have a lot of good ads. I'd spruce up your resume, too. Remember, you want to draw the eye to the items that will help you get the job you're applying for, so if you want an admin job, put those jobs first, even if they're not chronologically. Try to list more than use sentences, it's a report, not a letter. Try this objective: "To excel at a position as an administrative assistant that will challenge my current skill level and foster new growth."
I really think I got my current job because of my snazzy resume. I certainly wasn't qualified... ;)
As far as monster & careerbuilder, I did the same job Malibu's mom did for a while, and for a large firm that's actively looking for people to fill gaps, it's positive. But very few offices need to find people that way. The market is so open for admin jobs, that you really don't need to waste your time being hassled by people offering you jobs that you really don't want. But I guess that depends on how desperate you really are...
(If you're operation here fails, I've got an extra bedroom. :) )