We present a fully-polarized diffuse map of the southern sky (-1.6 to 7 hours RA, -50 to 0 degrees Dec) and discuss its applications for improved calibration and foreground removal for Epoch of Reionizaton (EoR) experiments. The map is produced with data from the Murchison Widefield Array (MWA) Phase I configuration and processed with the Fast Holographic Deconvolution (FHD) software package. Foreground mapping is a critical component of precision calibration of 21-cm cosmology instruments. Calibration solutions experience frequency-dependent errors due to foreground model incompleteness, and array redundancy cannot eliminate this source of error. Limiting calibration to short baselines only can eliminate the calibration error modes that contaminate the EoR measurement but relies on an accurate diffuse foreground model. We present a map of polarized diffuse (1- to 10-degree scales) foreground emission and discuss its implications for improved calibration.