Creloaded (Oscommerce) CSV Products Upload & Google Checkout

We are looking to add some new features to our website before launching the new version and need help with this. The features we need are: 1- CSV Inventory Upload from an existing Excel File. 2- Add Google Checkout to our Site Basic info about our website: Current URL until live: [login to view URL] OSCommerce is CreLoaded v6.2b2b This is a standard configuration but has had a modification for linking products installed as found here: [login to view URL] More details about what we need: 1- Our products are currently listed on Amazon UK and our inventory is stored in an Excel Spreadsheet for 15,000 products. We need to be able to easily convert this into a file/files which can be uploaded to our website SQL database. We will do this once a month so it needs to be quite a simple process which we can do ourselves. Our website already has "Easy Populate Basic" and "Easy Populate Advance" installed but we are unsure how to use these features with the Excel file. 2-We simply need the Google Checkout Module installed so that customers have an additional payment option.