Google now let you use Android Payment Extension for Google Checkout Store Gadget on your laptop to allow Checkout customers to purchase from their phones. "This extension helps merchants quickly set up a store and accept payments via Google Checkout and Android:
Create Checkout merchant account and configure your tax on Settings Tab, Use Checkout Store Gadget Wizard to generate webstore template, Fill in Google Spreadsheet with items you wish to sell, Create Google Sites page and follow wizard to embed Store Gadget, Install Android Payment Chrome Extension.
Once your customer tells you the items he or she wants to buy, you can create a cart with those items on your laptop. You then click green Checkout with Android button and have customer scan the QR code displayed with their phone. The QR code directs your customer to buy page where they can complete their purchase," explains Google.