I always leave it a little while too. Unless it's a serious negative, in which case I go asap.
If you still have the phone number, that could be included. State where you saw the ad and explain it's expired in the review.
For future reference, maybe a screenshot of the ad could help?
If you see her ad turn up again, post it in the comments.
If it doesn't count as enough info for a review, don't complain if it gets moved to the discussion section. Searching the phone number will still find it.
But that's only if you remember enough details about the name etc - realistically, most people aren't going to post each & every punt they have on here, if this one slips through the net I shouldn't worry about it.