You'll need longer screws & rawlplugs that go into the blocks/bricks and not just the plasterboard/ plaster. There's no other fix that'll work properly. A few Euro in Homebase and a drill with a hammer action and bob's your uncle. I do suggest that you drill the holes 1mm smaller and then open them out with the correct sized drill bit. That way the rawlplugs will anchor much better.My curtain rail,screws and rawlplugs all came out of the wall (the walls in places are powdery) and the intrepid diy-er that is she who must be obeyed fixed it back into the wall with 'no more nails' and it's held perfectly for more than a year.
I told her it wouldn't work ,as I frequently am reminded.