I have the Airport Extreme with AC in my brother's room but I wish to get a better signal in my garage. I'm going to get either another Airport Extreme or an Airport Express to extend its range. Which should I get? Is it worth spending that much money on another extreme to be put in extender mode since it would have AC and be able to extend both the 2.4 and 5ghz? Or would I be okay getting the airport express? Thank you.