This just in from ESA's Mike Steinkopf at ATV-CC:
Tonight's reboost was successfully performed using the ATV OCS (Orbital Control System) thrusters starting at 19:05 GMT / 21:05 CEST. The delta-V (DV - change in Station velocity) was 2.2 m/s for a 15-minute burn, which raised the ISS by 3.86 km to a higher orbit.
A DV of 2.2 m/s during 15 minutes is a very smooth increasing acceleration; the crew reported a feeling similar to sitting in a commercial aircraft.
The reboost was needed in order to set up ISS phasing for the upcoming Progress 47 launch, the Soyouz 28 undock & landing and Soyuz 30 launch.
Best regards, -- Mike from ATV-CC, Mission Director on console