osCommerce and Google Checkout integration/problems

Hello I am a Web Developer myself but I have no real experience of osCommerce and Google Checkout so I need some fast, reliable help. Willing to pay an excellent rate. BACKGROUND I have an osCommerce install (another developer did this) and a client who wants to use Google Checkout. REQUIREMENTS 1. I need the Shipping to work on the following basis: 1 item = £2.50 2 items = £3.50 3-5 items = £5.63 6+ items = Free (Plus show me where I can configure this for the future) At the moment, these are being specified using Weight (where each item has a weight of 1) in the osCommerce config (see attached screenshot) 2. I need the relevant shipping costs sent through to Google Checkout (at the moment 0.00 is showing, see attached screenshot) 3. A link back to Google checkout - on this page /shop/[login to view URL] for customers wishing to pay online. (client requirement not mine) PASSWORDS * I can supply all passwords etc. to access systems. FILES * Screenshot of Google checkout and £0.00 appearing * Shipping config screen (table rates) in osCommerce URGENT * ASAP please VERSIONS * Google Checkout Module Version v1.4.5_CCS * OSCommerce 2.2 RC2