In that case, I think any router will do as good, as long as the range is wide enough. Routers using an N connection usually have a range that can reach farther. Also, make sure that all the things you want to connect to your router can use an N connection. Otherwise, get something compatible.
The reason why I say it won't make a difference is that a router won't make your internet connection faster because that is limited by your ISP. A faster router will only mean a faster connection between the computers connected to the router (for example, a home network exchanging files.) If you are not doing any of this, a 100mbps router will do as good as a 1gbps router.
I hope I've been able to help!