I made the edits in this a while back for my server (Random advertisements seems better, less predictable for regulars). I've attached the source and compile to this post.
You can also !advertise 5 to show the advertisement 6th in your list of advertisements
I can't remember what else I added as I said, was a while ago, you can read through the source if you like, I've probably put in a few stupid comments to remind me of stuff, or just stupid comments because that's what I used to throw in my code.
If you want to shoot me the $15, can add me http://steamcommunity.com/id/SimplyJpk/
, won't turn down coin as I'm busy studying full time atm, however, if you get use out of it, I was glad to simply help out.
As far as I remember, it doesn't require any additional configs or setup, should work with your current config.
Take it easy,