So i've been using my airport express for airplay and printer sharing, so i've just connected it to my current network over wifi. Now i want to replace my router with the airport express, so i can have N. From what i understand, i just need to connect my airport express to my router/modem via ethernet. In airport utility, which type of set up do i choose? i literally just want to replace my router with the airport express. At the moment, i can see both networks (old router and airport express), can i just completely replace the router, so that the airport express is the only one that shows up?