Creloaded store - Require small script

2. On the admin side -------------------- I need a small script to increase/decrease price by x%. 1. For all the products in the store Provide a text box and increase/ decrease option. 2. For all the products in a particular category YOu need to present a drop down menu of categories, a text box and increase/decrease option in the admin panel. Admin will select the category from the drop down box and type percentage increase/decrese . Then the whole category product prices should change automatically Please bid if you experience in similar kind of code modifications. Payment after completion and can give excellent feedback for good work.