Time to start building a little excitement around your tour. Use the hash tag whenever you post about your book and be sure to mention the upcoming tour with any associated contest/prizes. Mention the tour on your own site, but don't overdo it. This is done best if you can work it into the regular content of your blog.
But it doesn't hurt to point your viewers toward the tour page and highlight any top tier sites you'll be featured at. A little promo goes a long way so I wouldn't do this until a week before the tour starts. Of course, get that banner or button up so it's always visible to any blog visitors.
The key here is to put the information out there without peaking too early. If you talk about your tour for a month before it happens, no one will care anymore by the time it gets here. When it comes to promo before the launch, less is more.