[Theme: Twenty-Twelve] Changing Entry-Meta AND Customized date

Basically I want to take the entry layout from the Contango theme and have in Twenty Twelve.

I can tweak some PHP, but this is a little beyond me.

I know how to style the date:

.entry-meta-group {
	margin: 0 0 25px 0;
}
.entry-date {
	display: block;
	text-align: center;
	background-color: #1cbbb4;
	padding: 8px 0;
	color: #fff;
	-moz-border-radius: 3px;
	-webkit-border-radius: 3px;
	border-radius: 3px;
}

.entry-date-day {
	display: block;
	font-size: 35px;
	line-height: 32px;
	padding-bottom: 10px;
}

.entry-date-month-year {
	display: block;
	font-size: 12px;
	line-height: 12px;
}

.entry-date a,
.entry-date a:visited {
	color: #fff;
}

But what I don’t know is how to write the function to make it show up.

Secondly..
I’d like under the headline to be: By AUTHOR · COMMENTS ? EDIT
Any tips on that?