customer has a partner systen with 7.0 processer and a 308 exp card. he is using all 8 co lines ports. we want to hook up an external paging system. i thought that you used one of the co lines ports if so since there are none open where do i install the paging system or do i need another card?

Much depends on what your expectation is. If external only is OK, you can get a station-level page adapter and connect to spare extension port. Call the extension, the page adapter rings and you speak. If you need simultaneous page then it must be via a CO position - so you'd need another card.
Mike