QUOTE(Sam-ChopinFan @ Feb 19 2010, 11:26 PM)

All you can do is practise, practise... and practise. Maybe pay more attention to your scales/arpeggios and practise your ocatves more. A good piece for practising octaves is Mozart's 'Alla Turca' - the B section of the Rondo uses Octaves in the RH, and large spread arpeggio's in the right - since learning this piece, large gaps and leaps have seemed a lot easier for me. Also, like someone else stated, you're still only 11. Your hands will grow to! Good luck and keep up the work

Wonderful Mozart piece you're working on there!
I'm learning the Rondo Alla Turca at the moment, and my arm strength has improved. If you can't physically reach the notes, have you tried spreading the chords. I'm 15 and have trouble reaching 9ths, so have to spread chords bigger than that.
Another piece that I'm learning at the moment with lots of octaves in it is 'Reveil dans les bois' by Burgmuller, which is probably about grade 6 standard. This has octaves for pretty much the whole piece in one hand or the other.