Top aides to Governor Eliot Spitzer of New York said Tuesday that they expected the governor to resign his office, a day after law enforcement officials said he was a client of a high-end prostitution ring broken up last week, although the timing of the resignation remained uncertain. Lieutenant Governor David Paterson and his staff have begun laying the groundwork for him to take over as governor, the aides said. As the governor pondered his decision, Assemblyman James Tedisco, a Republican and the Assembly minority leader, said he would begin moving to have Spitzer impeached if the governor did not step down within 48 hours.