I can't help you with what router you should use for an Apple product (though I imagine any decent router will work just fine), but I can tell you to be VERY careful with streaming with that Apple TV. Streaming in Hi Def will use up your data in no time, and even when streaming in SD or LD, you must be frugal. Satellite TV isn't really geared toward regular streaming. It's better you know this now than find out the hard way.
Also, during your first twenty days of service, your monthly data is reset daily. This is done to give you the opportunity to update/upgrade things without it affecting what would be your normal monthly data amount. So, what you may be able to do during your first twenty days you may not be able to do during a normal month. Just a heads up as so many people don't watch their data usage, stream like the dickens right at the beginning, then hit the wall on day 21 and wonder why.