Hi, Kat
A quick follow up: Just checked my copy of NWU's Freelance Rates and Standard Practice. You might want to consider giving them a price based on the word count (just as though you were selling it to a national weekly newspaper, for example). NWU recommends a rate between $0.30 and $1.00 per word for such work.
In any case, I would aim high and trust to your contact to begin negotiations if she thinks it's out of line.
(There are those who recommend a pricing structure based on a "per drop of blood exuded through the forehead during article prep and writing", but I must tell you frankly that NWU does not officially support this approach.)
Hope this helps!