I agree with everyone else. Take this job and keep your options open (especially if it pays more than what you're making now). At least by taking this job, your getting expose to the working world. You may learn something (ANYTHING) in reception and marketing that you could use when interviewing within the PR field. Granted, the two fields are different, but its not like you would be going from ..... say nursing to PR.
And don't worry about quiting about a month or so. I know folks that have taken job and have wuit after 2 weeks (because something better came along at the last minute).