Sorry to hear that the fracture you sustained has not healed yet. The fracture of forearm bones on an average take about 6 weeks to heal. But again it depends on whether the bones have been in good alignment and immobilsed with plaster properly or not. Sometimes if a small portion of muscle gets caught in between, that can delay healing.
Next Steps
I would suggest to get the x-rays assessed by an Orthopaedic surgeon. It does sometime take longer for the bones to unite. There is no harm in giving it few more weeks in cast provided the alignment is good.
Health Tips
Avoid smoking as that can delay healing of bones. Secondly, healthy balanced diet, Vit D,
Calcium supplements can help.
Best wishes.