connectto on "page w/ posts - pagination - twenty eleven"

so i have a page that shows all post from a selected category

http://www.connectto.com.br/websites/portfolio/

but need to have a pagination in this content, so it would show just 4 posts in each page

im using a copy of twenty eleven, heres my code for this page
category-portfolio.php

http://pastebin.com/UN3BCvHP

also have some problem in my content background - should be black with some transparency as my home http://www.connectto.com.br/websites/ - but this bg isnt there ...

help please ! :D