You are correct that word order matters for emphasis, but there doesn't appear to be any hard-and-fast rule (e.g., the first word isn't always the most important). For anyone who's interested, here's the relevant Wikipedia article. Take it with the usual Wikipedia grain of salt.
Agreed, that it is a mean trick to have played!
As Bail observed, the convention is for the adjective to follow the relevant noun; but it is not compulsory.
I presume the point of this sentence was to catch the unwary, and to remind everybody that, in Latin, it isn't just the word order that matters, it is the matching cases:
nostr-AM and urb-EM match as they are both Acc. case.
'femin-AM nostr-AM visitamus' would match, in the Acc. case: 'we visit our woman'.
'femin-A nostr-A urbem nostram visitat' would also match, in the Nom. case: 'our woman visits our city'.
But, as Syimyuzya explained, it cannot be 'our woman visits the city'.
Hard to say without context, but I'm guessing "quedam" is actually "quaedam", so it could be "Because/which a certain woman of ours..." or "Because/which a certain one of us women...". It seems to be trying to specify a particular woman among many (which belong to a group that includes the author?).
Online Etymology Dictionary offers: nostrum (n.) c. 1600, "a medicine made of secret ingredients by secret methods," but commonly "quack medicine," from Latin nostrum remedium "our remedy" (or some similar phrase), presumably indicating "prepared by the person offering it," from Latin nostrum, neuter of noster "our," from nos "we," from PIE *nes-(2); see us.In extended use, "a pet scheme for accomplishing something" (1749).