Since you want to send HTML email from your Gmail account and don't want to write Java or PHP, I suggest you check out Google AppScripts
.
Inside the AppScripts editor, you can create the HTML template and send it as is using the following code.
var htmlEmailBody = HtmlService.createTemplateFromFile('html-template-name');
var subject = "Welcome to Google AppScripts";
var toAddress = "xyz@xyz.com";
var normalBody = "This is the normal plaintext version of the html email";
GmailApp.sendEmail(toAddress, subject, normalBody, {
htmlBody : htmlEmailBody.evaluate().getContent()
});
}
However, there are several things to follow when sending an HTML email like inlining all CSS styles, using table layouts, and more. I suggest you read my article on the same here.
Head over to script.google.com to start writing your first AppScript.