a) There's many of us promoting Amazon products and what you will find is that there's 2 prices going there; the full price and the discounted price. To be able to have the extra field to enter the discount price + link and anchor would be great.
b) A nifty little addition to that would be comparing the full price against the discount price to work out the percentage of discount for displaying.
Also: Review box layout
A bit more control over styling would be a vast improvement. Such as being able to set default colors, dimensions, thumbnail size and so on.