I want to learn to play piano/keyboard and I do not know where I could obtain some of these sheet music. For example, 'Sorry Seems To Be The Hardest World', 'Total Eclipse Of The Heart' or some of Goodrem Delta. Thanks in advance. ^_^

Try your local music store.

Here, there aren't shop, local shop with cd's, instrument, music, or similar... For this reason, I'm here...

Where are you writing from?

maybe you could look on a online music store for a book because they have books for specific band songs and they usually have the melody in it too.