I recently injured my elbow through sport.

Upon impact it dislocated and fractured.

I went to the hospital again yesterday (three weeks after the incident) and they say that the fracture isn't bad but there may be some damage to the soft tissue.

I can't fully straighten my arm, and i can hardly move my forearm towards my bicep at all. There is a lump on my inner elbow which is going down slowly, i think the doctor said this is a clot, i think it's this that's stopping the movement?

Will this movement come back in time, how long does it take for a fracture to be fully healed?

Elbow fractures are difficult- the average loss of motion following an elbow fracture is 30 degrees. You may get all, or most function back, depending on the location/type of fracture, allignment of the fracture fragments, how well you heal, how compliant you are with therapy. Fractures involving articular surfaces are generally more problematic. Get some therapy (OT or PT), but don't be overly aggressive, as the elbow is prone to heterotopic ossification when stretched too aggressively. Good luck.