I half agree with your suggestions, guys.
Not that you shouldn't buy her an extra $50 present (I'm all for it).
I suggest you buy her something before Christmas, on no particular day. Doesn't have to be jewels or else. How about flowers, a night out, a concert, ballet maybe?
The way I see it, gifts are so predictable when given at Christmas, birthdays, and way too predictable on Valentine's day.
If she's extraordinary, you got to treat her that way... and that's any day (everyday) of the year.