Find a curtain track or rail that fits, remove the baton that's already there, screw the new track to the baton, then glue and screw the baton to the wall. You obviously won't be able to screw the baton where it is overlapped by the wardrobe, but if its a reasonably stiff baton and you glue and screw it to the wall as close to the wardrobe as you can, it will be fine.
Alternatively, fit your curtain rail inside the window reveal as your blind is now.
A real left field option would be to reverse one end of the curtain pole bracket and screw into it from the wardrobe, rather than into the wall.