GTranslate and Quick2Cart

Hello

I am working with GTransalte and I see a problem with Quick2Cart Addon for Jreviews.

If I go to a translation, the "buy now" button does not work.

I contacted GTranslate and the told me to find tis javascript variable:

var qtc_base_url = 'http://www.mysite.es/';

You need to replace it with:

var qtc_base_url = '/';

Which will fix the issue.

My question is, where can I find this variable? in what file?