Day nappies at night never worked for us, DD was in night nappies at 8 weeks old once she started sleeping through. Try a WNNN (they have just got a new version out but i havent got one of these, there is probably some of the older styles on the classifieds. These have a bamboo insert, i find these very abosrbent but i do boost with hemp too and use wool or a fleece soaker.
UDNN are brilliant but they are only open to the trade at the moment, though online nappy stores do stock them, again probably some on the classifieds bit. Their french soy ones are FAB!