The public library recently received a $1,250 donation from the Rotary Club of Woburn. Kathleen O’Doherty, the library’s director, said the unrestricted gift will be added to the building fund the library maintains for its planned renovation and expansion. Meanwhile, the library is planning a fund-raising event to benefit that project on May 2 from 5 to8 p.m. at the 99 Restaurant, 194 Cambridge St. The restaurant has agreed to donate to the library 15 percent of the proceeds of any meals purchased by patrons who present a voucher. To obtain a voucher, stop by the library or go to www.woburnpubliclibrary.org. The state Board of Library Commissioners in 2011 approved $9.9 million for the Woburn project, preliminarily estimated to cost $24.5 million. The city is now third on a waiting list to receive a grant once the state money becomes available. Library officials hope to cover the remainder of the project costs through private donations and city funds.