Adding a calculated product price within Magento based on Gold and Platinum Prices

Product Price Calculation Need two new text boxes with ability to change the gold price and platinum price on a daily basis and then calculate product price based on this. Needs to be a sub menu item with text fields somewhere under one of the top menus. One text box for gold price and one for platinum price. There are 4 types of prices taken from the attribute: product-type • Set Price • 9ct Gold • 18ct Gold • Platinum 4 Calculations: 1. Set Price Nothing needs to happen with this as it is the actual product price 2. 9ct Gold First Calculation is to get the price per gram: Gold Fix Daily Rate – (variable from user input text box) * 0.375 / 31.1035 = Price Per Gram Example: £800 * 0.375 / 31.1035 = £9.64 per gram This calculation can be done once when the gold price is changed and stored? (variable number needed) Second Calculation is to get the product price: Price per gram + Labour rate (currently product price) = Labour & Gram Combined * Product Weight = Product Price Example: £9.64 (Price per gram) *£5.00 (current product price) = £14.64 (total) * 10 Grams = £146.40 3. 18ct Gold First Calculation is to get the price per gram: Gold Fix Daily Rate –( variable from user input text box) * 0.750 / 31.1035 = Price Per Gram This calculation can be done once when the gold price is changed? (variable number needed) Second Calculation is to get the product price: Price per gram + Labour rate (currently product price) = Labour & Gram Combined * Product Weight = Product Price Example: £9.64 (Price per gram) *£5.00 (current product price) = £14.64 (total) * 10 Grams = £146.40 4. Platinum First Calculation is to get the price per gram: Platinum price / 31.1035 = £32.15 (Price per gram) Price per gram + Labour rate (currently product price) = Labour & Gram Combined * Product Weight = Product Price