You might be able to hurry things along by taking action via the tenancy section of Fair Trading for a reduction in rent backdated to when the termites were first discovered until the problem is fixed, on the grounds of disturbance and loss of amenity. Call Fair Trading on 13 32 20 or have a look HERE for the Tenants Union fact sheet on repairs.
Maybe just telling the agent if this isn’t fixed pronto you will ask for a rent reduction might be enough to get things moving.
Perhaps the builder’s number was given to you so you could co-ordiante your movements with theirs (if they were actually moving).