TitanTV.com has listings a week or so in advance. Not sure how to do off-air listings, but I've been using it for cable & satellite listings for years.
Why not try TitanTV com? It's 24/7 coverage for the next 2 weeks, with program descriptions, searches, etc. And you can reconfigure it to put the channels in the order you want. It's free (with ads) over the internet.