CDMS II data from the 5-tower runs at the Soudan Underground Laboratory were reprocessed with an improved charge-pulse fitting algorithm. Two new analysis techniques to reject surface-event backgrounds were applied to the 612 kg days germanium-detector WIMP-search exposure. An extended analysis was also completed by decreasing the 10 keV analysis threshold to \sim5 keV, to increase sensitivity near a WIMP mass of 8 GeV/c^2. After unblinding, there were zero candidate events above a deposited energy of 10 keV and 6 events in the lower-threshold analysis. This yielded minimum WIMP-nucleon spin-independent scattering cross-section limits of 1.8 \times 10^{-44} and 1.18 \times 10 ^{-41} cm^2 at 90\% confidence for 60 and 8.6 GeV/c^2 WIMPs, respectively. This improves the previous CDMS II result by a factor of 2.4 (2.7) for 60 (8.6) GeV/c^2 WIMPs. Show Partial Abstract