Speed question of g vs n

[BoogerBomb]

I currently have Uverse that comes with the 2 wire combo gateway. I have one computer and my new touchpad that have .11n capabilities. I subscribe to the 18mbps internet package and average 13 to 14 mbps down when I check each of them on speedtest.net. I started ripping my blu-rays to be able to stream them to other devices in the house and was wondering if getting my own .11n router and putting it in the DMZPlus mode would result in faster internet speeds or if it would have higher realized speeds while streaming blu-ray movies throughout the house?