Hi Swe,
In simple terms:
HR Director - is a person who sits on the Board of Directors with special responsibility for HR. He will direct (to the HR Manager) which polices are required for the proper functioning of the company. He is also responsible for keeping up to date with all legislation regarding Employment law, and filtering such information to the HR Manager. He may also take part in formulating procedures, rules and regulations. In case of a dispute he is the ultimate authority within the company, though he can be overruled by the Managing Director, who in turn can be overruled by the Board. He is also responsible for all recruitment, including recruitment at Board level. He should work closely with the HR Manager.
HR Manager - is responsible for the day to day HR issues, unless they need to be escalated to the HR Director. He is also responsible for ensuring procedures, rules and regulations are adhered to and all relevant documentation. He is the first port of call for any issues. He is, usually, responsible for and will handle all recruitment at junior management and below, though the HR Director may be involved at some stage.
Therefore, there will be some overlap between the two, which is why they should be working very closely.
Hope the above helps.
Regards,
Harsh