Hi sir. So you need help with your checkout pages and payment gateways and afterwards store the orders in a mysql database, I can do that for you sir. I'm very experienced with PayPal and Google Checkout, and I have completed similar projects before. I'm an experienced Web Developer having worked for 5+ years with PHP, Java, Solr/Lucene, Sphinx Search, Smarty, MySQL, SQL Server, ASP, JavaScript, Ajax, JQuery and CSS.
Please check your inbox(PMB) for further details about my expertises.