Wherever in the document you need a new Header or a new Footer insert a sectoin break.
In Word 2007, inserting a section break is located in the Page Layout tab. (You'd think it would be in the Insert tab, but it isn't...go figure.) So...
1) Left-click on Page Layout.
2) Left-click on Breaks in the group Page Setup and select "Section Break...Next Page"
3) In the new section, double left-click in the header to edit it.
NOTICE that the Ribbon has automatically switched to "Design"
4) In the group labeled "Navigation" left-click on "Link to Previous" to undo the link.
5) Edit the section header to your liking.