allow relative date view filters

I need the date module, when being used as a filter for a view, to be able to use a relative date (like 'this Sunday'). I hacked around a bit on date_views.inc and came up with the code below. On the filter for the view, I'm using '@RELthis sunday' as the filter value.

  switch ($filterinfo['type']) {
    
    case ('DATE'):
      if ( substr($filter['value'], 0, 4) == "@REL") {
        $date = "'" . str_replace('T', ' ', date_unix2iso(strtotime(substr($filter['value'], 4)))) . "'";
      }
      else {
        $date    = $filter['value'] == 'now' ? "NOW()" : "'". str_replace('T', ' ', date_custom2iso($filter['value'], $formats['input']['text'])) ."'";
      }
      break;
    default:
      $date = $filter['value'] == 'now' ? date_sql($filterinfo['type'], "NOW()", $field_type, '') : $filter['value'];
      break;
  }

This is getting the correct date into the SQL where clause, the I can't figure out how to get the correct time. Somehow I've got to figure out how to get the correct timezone into the date_unix2iso function (assuming I need that function at all).

I think this would be a valuable addition to this module. In my case, I'm doing a website for my church. We have the church assembly times on the site, so I created a CCK node type and associated view. It is _great_ that I can filter the view based to show the assembly nodes where the assembly date is greater than now(). But, if my users don't enter an assembly for this Sunday, but they do for next Sunday, then I don't want to show the block on the page at all. In other words, I only want to show the assembly information when there is an assembly entry for this Sunday.

If I can figure out this timezone issue, I'll be happy to roll a patch for consideration.