Sally Jessy Raphael has signed a new five-year contract with Multimedia Inc. worth $ 25 million; the deal carries her successful syndicated talkshow through the 1997-98 TV season.“Sally is a huge asset for Multimedia in maintaining its position as the premier producer of talkshows,” said Bill Carroll, VP and director of programming for Katz TV, the TV-station rep firm. Multimedia also produces and distributes “Donahue,”"The Rush Limbaugh Show” and “The Jerry Springer Show.” In addition, the company is planning an all-day cable network called the Talk Channel, with a fall 1994 target date. How she grew Carroll says Multimedia has nurtured “Sally Jessy Raphael” carefully over the last decade, from its beginning as a local half-hour talkshow seen only in St. Louis to a 60-minute strip that’s cleared on 213 stations covering 99% of the U.S., according to the latest Nielsen tally. Although “Donahue” is the granddaddy of talkshows, having run continuously in firstrun syndication for the last 27 years, the Raphael show tends to eclipse “Donahue” in the women 18-49 category and in recent weeks harvested better Nielsens than Phil in the household-rating category. The Raphael show has even begun to make slight inroads against King World’s “Oprah Winfrey Show” in individual markets when the station has moved it to a timeslot directly opposite Oprah, Carroll said. Raphael, he added, “has had some success against Oprah in targeting the younger female viewer.” Raphael begins her 10th season Sept. 6, with Burt Dubrow as executive producer.