The cynic in me says, "Really, you'll miss the series that made you the richest woman in England? No way."
However, part of me doesn't think it'll just be 7 books (I have not read book 6). At some point in time in book Order of the Phoenix (5), Harry thinks about what he'll do for a career and stuff. He thinks he might want to go to the wizard equivilent of college/grad school or something, either way it takes 3 years. I wouldn't be surprise if we got those 3 years of college at some point in time (though I do think she'll take time off after book 7 comes out, I wouldn't put money on it being Harry's last adventure).