According do this post, Wine's locale settings (like numbering format) is based on Ubuntu locale settings.
If I have to change my Ubuntu locale settings, how can I change locale settings in Ubuntu 12.04, making sure that "monetary" and other numerical format settings will be updated too?
To change local in Ubuntu, go to System Settings --> language settings, and click on the Regional Formats tab. Change it to the desired country, and close the window. Logoff, and log back in or reboot your system.