As you said, my own understanding of the Faith is limited, which is why I trust my priest when he tells me that it is not sinful to be employed by a Protestant church.
As far as "exposing" myself to the occasions of sin, etc - would be sinful for you to even walk outside when other people are around because you might overhear something sinful, etc?
Where do you work? I'd almost be certain that if it wasn't an overtly traditional Catholic employer you would be exposed to the same amount, if not more, of occasions of sin as I am when I am in the workplace.