Hi Scout1420,
What does your physio do with you at the moment?
From what it sounds like after a period of time of immobility naturally all the joints will be stiff as well as the muscles. The muscles that control your hand originate at your elbow so it has to travel a long distance and work over this which may contribute to the stiffness and weakness. My suggestion is to massage the swollen area especially over the fracture site, you can use any cream, heat cream, moisturiser but its the blood flow that you want to get going to the area. 10-15 minutes of strong massage will help increase the blood flow and lengthen all the tissues that have been tight for a month. COmplete this twice daily in the morning and night. Massaging on top of the area and also in the bulk of your forearm. If you look would notice that the forearm muscle bulk is less than your right which suggests its weaker.
Stretching is also important and helpful Wrist exercise - wrist extensor stretch - YouTube
If your physio is not doing any hands on or manual therapy which is joint mobilisations on your wrist and hand I would strongly advise you to consult a physiotherapist that does manual therapy as they will help mobilise the joints to reduce the joint stiffness present post immobilisation. A couple of sessions should help.
Hope that helps.
K