The easiest way to this building is to take metro line 3 (blue) and get off at Lehel tér (square). If you come from the centre, go out in the rear of the subway. There is the beginning of Victor Hugo street, and the building is at the third corner.
Other possibility is trolley 76 from the Keleti pu. (Eastern Railway Station). You get off at the next stop after Lehel tér.

Map of the region.