As I've written before, this economy requires much stronger medicine but given the to and fro about the tiny stimulus package, it doesn't look like it will get it. People have compared this crisis to the "Lost Decade" in Japan after their real estate. While we will probably avoid the worst extremes of inflation and deflation, we may muddle through the middle ground for several years; without the political will and vision to begin to clean up the problems (in all sectors of the economy, not just the banks.)
How much would it cost? It is hard to be precise but $7 trillion seems a reasonable order of magnitude. Even if we wanted to spend that much in one year, I doubt we could get away with it but we could easily spend the next eight years cleaning up for the last sixteen.