Custom date display for the whole site

Any idea how do I set dan do the function overrides to display the overriden date display so it may also available through a page.tpl.php? Let me make myself clear.

I have overriden e.g: February to Februari (it's Indonesia). It all works for node creation display, thanks, but when I echo date('Y-M-D') in my page.tpl, it goes back to English part. I suppose there must a way to make the overriden phrases also available for the whole site. Any ideas to do that? Thanks for the module.