It would definitely help if you just read the API documentation, but here is some sample code that should give you an idea:

<!-- language: lang-cs -->

    [TcmExtension("ExampleEventHandlerExtension")]
    public class EventHandler : TcmExtension {
      public EventHandler() {
        EventSystem.Subscribe<Component, SaveEventArgs>(ComponentSaveAction, EventPhases.Processed);
      }

      public static void ComponentSaveAction(Component subject, SaveEventArgs args, EventPhases phases) {
        // the TCMURI of the Publication from this item
        TcmUri contextRepository = subject.ContextRepository.Id;

        // the TCMURI of the Publication where this item was localized
        TcmUri owningRepository = subject.OwningRepository.Id;

        if (subject.IsLocalized) {
          BluePrintChainFilter filter = new BluePrintChainFilter(subject.Session) {
              Direction = BluePrintChainDirection.Down
            };

          // the TCMURI of the Publication where this item was created
          owningRepository = subject.GetBluePrintChain(filter).FirstOrDefault().Id;
        }

        // build TcmUri of parent Component
        // (note using ItemId of owningRepositiory as a PublicationId, 
        //  since that is a Publication TcmUri)
        TcmUri uri = new TcmUri(subject.Id.ItemId, subject.Id.ItemType, owningRepository.ItemId);
		
        // load parent Component
        Component parent = new Component(uri, subject.Session);
      }
    }

**Note** I didn't test any of this, it is just an example to give you an idea of what you can use, please read the API documentation for every method shown here to see if it indeed is what you require.

If you need the same info via the Core Service see my answer to
http://tridion.stackexchange.com/questions/4520/how-to-get-the-owning-publication-of-a-component-via-the-core-service