You can always get any version of Warband directly from Taleworlds.
Simply change the links to fit the version you want:
http://download.taleworlds.com/mb_warband_setup_1143.exe
or
http://download.taleworlds.com/mb_warband_upgrade_1100_to_1143.exe
Just change "1143" to "1142"...or if you want the last vetted, stable version, "1134".