i'm not good at directions but there's a thrift shop near the back entrance of Gaisano Main. opposite side so u still have to cross the street from the back entrance. unya subay na lang dayun sa dalan. i can remember a candle shop before the thrift shop. not well lighted so it might easily be missed. you'll see other sorts of items for sale there, not just books. just keep in mind you are headed towards the Visayan Restaurant. only layo na kaayo to.
anyway i like the term "bookay bookay." hehe.