chevrolux: If you decide to go with either I would say use pfsense to do the routing.
I also suggest you get a decent router first, as that is the cheapest. Any old PC will do, and you can pick up bargain $40 servers at trademe. They won't look great (rack servers), and might be a bit power hungry, but you can start with them cheap. Note your server needs to NICs, so one NIC goes into the ADSL modem, the other your switch/wifi router.
With pfsense you can reserve bandwidth for your voip, and setup other QoS. Simply start with the wizard, and you probably won't need any tuning with that.