The Labor Department or college office should help you – that’s lot better than just looking online at Monster or something.
Are there any frum businesses (not chessed orgs!) in your area, where Shabbos won’t be an issue? Alternately, maybe you can look for an office job in a non-frum setting, where it’s 9-5 Monday through Friday? Most places should accommodate leaving a little early winter Fridays if you explain how you’re happy to come in early or stay late to make up the time. Maybe a medical office?
As an aside, what kind of tax forms were you asked to fill out before getting an offer with details? Don’t provide your social security number. If you’re applying at a major corporation where they want to run a background check that’s one thing but by that point you’ll know how much they’re paying.
Hatzlacha rabbah!