Do this by editing the stylesheet for your custom template(the one you created)
Find this code:
Code:
.leftBoxContainer, .rightBoxContainer {
    margin: 0em;
    border: 1px solid #000000;
    border-bottom: 3px solid #000000;
    margin-top: 1.5em;
	}
Separate and change to this:
Code:
.leftBoxContainer {
    border: 1px solid #000000;
    border-bottom: 3px solid #000000;
    margin-top: 1.5em;
    margin-left: 5px;
	}

.rightBoxContainer {
    border: 1px solid #000000;
    border-bottom: 3px solid #000000;
    margin-top: 1.5em;
    margin-left: -5px;
	}
You can adjust the values but should also adjust the column width in the admin >
configuration > layout settings. If you add 5 or 10 px margin add that to the left and right coulmn widths.

Note the right has the margin-left as a negative value...I have tried margin-right as a positive value and this does not render correctly, the negative value does