I believe that is the correct behavior. Looking at an aircraft PFD can be a bit counter intuitive but imagine the brown half of the circle as the line of the horizon. When the aircraft rolls to the right you will see the right side of the PFD come up (imagine you are looking out of the cockpit of a plane).
To check the signs on your attitude readings you can look at the "ATTITUDE" message in the messages window of paparazzi. When you roll to the right you should see a positive roll indicated (and negative to the left). Similarly pitching up is positive, and clockwise yaw (looked at from above) is positive.
Andre.