When exiting Liszt Ferenc airport, egt on the 200E bus. Take it to Kőbánya-Kispest metro terminal. Get on the blue metro, and go all the way to Deák square. Get off and find Bajcsy-Zsilinszky way. Walk until you find Bajcsy-Zsilinszky way 17! Remember, you will have to buy 2 tickets to make this journey (on for the bus, and one for the metro!).