We've seen plenty of VoIP solutions and video streaming alternatives to standard phone lines, but sometimes a fast internet connection isn't enough. When sub-par quality of service becomes an issue, it's time to hit the router options and tweak it for optimal connectivity.
According to PC World (where this guide is originally based off), the best way to optimize your bandwidth to allow bandwidth-heavy services like video and voice is to use a combination of port forwarding, QoS, and splitting of your traffic between two separate wireless networks to allow bandwidth-heavy stuff to travel through one pipe, while allowing the rest to go through the other.
The idea here is that allowing separate channels to handle the workload is better than having a single stream trying to allocate accordingly. Wireless routers, despite how advanced they are these days, just can't keep up (it's also very apparent with wireless HD streaming, which can benefit from the same treatment).
You can check out the PC World guide for the full details on how to go through the tweaking process.