These settings are in the registry under HKCU\Control Panel\International
You can use reg.exe to make changes manually. The easiest way to do this is to manually change the region and language to Spanish (mexico), open the cmd window and type reg query "HKCU\Control Panel\International"in which will show you the values you want. Then, to change them, use REG ADD "HKCU\Control Panel\International" /t REG_SZ /v LocaleName /d es-Mx /ffor each value that replaces that after / v with the corresponding name and that after / d with the corresponding value.
- HKCU\Control Panel\International .reg , regedit /s ImportFile.reg
, . , . RUNDLL32.EXE USER32.DLL,UpdatePerUserSystemParameters ,1 ,True