date = datetime.datetime.today()

filter(datetime__range=[date - datetime.timedelta(days=7), date])

filter(datetime__gt=date - datetime.timedelta(days=7))

class TimezoneMiddleware(object):
    def process_request(self, request):
        tzname = request.session.get('django_timezone')
        if not tzname:
            request.session['django_timezone'] = 'Europe/Kiev'
            tzname = 'Europe/Kiev'
        timezone.activate(pytz.timezone(tzname))

TIME_ZONE = 'UTC'