Convert Custom PayPal button to Google Checkout Button/Cart

I have a simple PHP page that has one Pay Pal button embedded. I need the Pay Pal button to be converted to a Google Checkout add to cart button. You will be given the php file and I will need the php file back with the new code integrated. Here is a portion of the button code: <input type="hidden" name="on0" value="Letter Height">Letter Height: <select name="os0"> <option value="2&quot;">2&quot; $7.99 <option value="2.5&quot;">2.5&quot; $8.50 <option value="3&quot;">3&quot; $9.50 <option value="4&quot;">4&quot; $10.99 <option value="5&quot;">5&quot; $13.99 <option value="6&quot;">6&quot; $17.99 </select> <br> <input type="hidden" name="on1" value="Color">Color: <select name="os1"> <option value="Black">Black <option value="White">White <option value="Red">Red <option value="Blue">Blue <option value="Green">Green <option value="Pink">Pink <option value="Orange">Orange <option value="Yellow">Yellow <option value="Silver">Silver </select> <br> <input type="hidden" name="on2" value="Font (Lettering Style)">Font (Lettering Style): <select name="os2"> <option value="Arial Black">Arial Black <option value="Impact">Impact <option value="Americana">Americana <option value="Artcraft">Artcraft <option value="Auburn">Auburn <option value="Baker Signet">Baker Signet <option value="Bank Gothic">Bank Gothic <option value="Baskerville">Baskerville <option value="Bauhaus">Bauhaus <option value="Belwe">Belwe <option value="Bengel">Bengel <option value="Bernhard">Bernhard <option value="Birch">Birch <option value="Block">Block <option value="Bloom">Bloom <option value="Branding Iron">Branding Iron <option value="Broadway">Broadway <option value="Comic Sans">Comic Sans <option value="Computer">Computer <option value="Corsiva">Corsiva <option value="Courier">Courier <option value="Davida">Davida <option value="Egyption">Egyptian <option value="Flare">Flare <option value="Gem">Gem <option value="Gore">Gore <option value="Hobo">Hobo <option value="Impact">Impact <option value="Isbell">Isbell <option value="Korinna">Korinna <option value="March">March <option value="Mirarae">Mirarae <option value="Mobster">Mobster <option value="Moon">Moon <option value="Nueva">Nueva <option value="Orca">Orca <option value="Omega">Omega <option value="Paplar">Paplar <option value="Pointedly">Pointedly <option value="Poster">Poster <option value="Rounded">Rounded <option value="Cheap Fire">Cheap Fire <option value="Snow Caps">Snow Caps <option value="Thunderbird">Thunderbird </select> # <br> <input type="hidden" name="on3" value="Your USDOT number:">Your USDOT number:<input type="text" name="os3" maxlength="30"> * <br><br> <input type="hidden" name="currency_code" value="USD">