It usually takes a month or more to cycle a tank completely, so I wouldn't get too worried yet. One thing that I like to do when cycling a new tank (I'm sure some aquarists don't agree), is to put a piece of filter media directly in the tank that was taken from the filter of a well established, healthy tank. It usually serves to jump-start bacterial growth. Driftwood, rocks, or even substrate will also work; anything that has a surface area where bacteria can grow well, but filter media seems to work best for me.