This way will help you out
+ Open language/en-GB/en-GB.tpl_ja_nuevo.ini file
Find and change
K2_DATE_FORMAT_LC3="M <b> d </b> "
to
K2_DATE_FORMAT_LC3="M <b> d </b> Y"
+ Open templates/ja_nuevo/css/k2.css file
Find and change
div.catItemHeader .catItemDateCreated {
width: 60px;
height: 60px;
border-radius: 50%;
background: #73bfe6
text-align: center;
color: #ffffff
display: inline-block;
vertical-align: middle;
overflow: hidden;
line-height: 1;
padding: 10px;
}
To
div.catItemHeader .catItemDateCreated {
width: 60px;
height: 60px;
border-radius: 50%;
background: #73bfe6
text-align: center;
color: #ffffff
display: inline-block;
vertical-align: middle;
overflow: hidden;
line-height: 1;
padding: 5px;
}