Powered by PunBB © .... at center

Add this at the bottom of your css.

p.conr {clear: both; float: left; text-align: center; width: 100%;}
ul.conr {clear: right; float: right; text-align: right;    width: 40%}

.conr is defined in base.css and affects both the copyright text and the "Show new posts since last visit/Mark all topics as read" part therefore I used p.conr to affect only the copyright and ul.conr, which is the very same of .conr in the base.css, to put the "Show new posts" back to its place. I didn't notice any other forums' parts affected by .conr, if you notice something strange let me know.

p.conr {clear: both; float: left; text-align: center; width: 100%;}
ul.conr, p.stats {clear: right; float: right; text-align: right;    width: 40%}

And

<p class="stats"><a target="_blank" href="http://blablabla"><img width=88 height=31 border=0 src="http://www.blabla alt="bla Bla bla"></a></p>

Watch that target="_blank", it makes your page XHTML 1.0 strict not valid.

I tried some but the result is not acceptable, I'm afraid it's beyond my skills.