Hi @arafath,
Welcome to the Bunnings Workshop community, it is fantastic to have you with us.
Fixing the issue should be broken down into two parts. Reattaching the curtain and then fixing the damage.
Ideally, the curtain hooks should be attached to the wall framing, as the framing will offer much more support than the plasterboard. If you can, use a stud finder to locate the studs, then attach the curtain brackets to those studs with suitable fixings. These 30mm Plasterboard Screws will work. If you can't locate studs, then you'll need to use plasterboard anchors. Whichever option you use, the brackets will need to be moved by at least 100mm to the left or right, as the plaster around these holes is fractured and no longer suitable for attachment.
Once the curtain brackets are reinstalled, you can use How to Fix a Hole in the Wall as a guide for repairing the holes. Also, here's a helpful guide: How to repair and install a curtain rail.
Let me know what you think, and if you have further questions, please don't hesitate to ask.
Jacob
