have you done anything to make yourself look more attractive for the job, eg publish newer articles? if so, attach those. if not, then maybe don't apply this go-round - seems like this job keeps opening up, maybe for a reson? and really show them next time why they should consider you. if you really wanted to be a stringer, you would already be out there. are you just looking for them to reject you again?
ETA: I know it's really hard to judge this as a bp - everything always sounds like such a good idea at the time.