Your memory is WAY off. It may seem that way, but Bush didn't announce the Alito nomination until October 31. It might work out to seven months if you add the Harriet Miers misstep.
http://www.supremecourtus.gov/publicinfo/press/oconnor070105.pdf
Her retirement letter is dated 7/1/05. Aug, Sep, Oct, Nov, Dec, Jan, Feb. Sorry one day short of seven months.