Tig, I don't know your exact situation but I have a similar one. Try to think of a gift with meaning. An iphone is an awesome gift but at 12 it may be a little overkill (and she risks having it stolen by a classmate with envy).

Are there any good souks in town with quality, unique gifts (assuming you haven't gone that route already)?

I think Gypsy might be right, Tweenies love to feel grown-up so being pampered or having fashionable clothing may get a lot of mileage.

For what it's worth.