Once he's dead go through a closet with a light in it and a shelf behind a box. Go up the stairs and continue through a final glass doorway (there's a lot of doorways) into a room with a mutated dwarf in it.
Continue through the hole and then go through yet another doorway with a light under it after you pass through it. Crouch under it then pass through a shower room with a large hole in the wall.
Keep going until you are in a hallway, and take a left where there is another doorway with a large board on it. Continue on until there is a second doorway with a single board across it, which you can destroy the same way as before. Just knife or shoot the boards to destroy them, but there will be electric anomalies behind the doorway. Once you get there, you must travel through and find a doorway boarded up with two boards across it. The second set of calibration tools are located at the Old Service Center. When you get to a room with stairs going to a basement, go down the stairs and on a table will be the set of tools. There is a maze of doors as you enter so try to get through as best you can. Inside there will be a large number of Hamsters, so carrying a shotgun would be recomended.
When you enter, go behind the main desk and open the door. The first set of calibration tools in Pripyat will be located at the Department Store.