more on this:
ok so i found get_archive in wp-includes/template-functions-general.php
i found that if i change line 304 from this:
$url = get_month_link($arcresult->year, $arcresult->month);
to this
$url = get_month_link($arcresult->year, $arcresult->month).’&cat=2′;
i get what i want (except that it yields months when other categories had posted and the desired one did not ). but i find this method kinda inelegant. I would rather use a plugin, maybe that adds a new function ‘get_archiveBYcat’ or something but once again i dont know really how to write that, any ideas?? thanks