Hello,
You should be able to add a simple margin-bottom css call to the coding below to add some more spacing.
com_content.css - line 369
p.readmore a.btn {
border: medium none;
box-shadow: none;
color: #ffffff !important;
cursor: pointer;
display: inline-block;
filter: none;
font-size: inherit;
line-height: inherit;
text-align: left;
text-shadow: none;
text-transform: none;
}