OK, I see what your speaker system is.  I have never seen one of those before.  Just be aware that adding an N router may or may not solve your problem.  Also, it's a little complicated.  You will have to reconfigure some of the settings on your RG and configure your new router properly and then plug it into your RG.  Then you will have to reconnect all of your wireless devices to the new router.  Those will include laptops, smartphones, speaker system, wireless printer (if you have one) etc.  Make sure you're up to it.  I use a CradlePoint router.  I'm not sure what another good option might be.