To be honest, I've never used those features so I'm not one to speak about them however the OP is having bandwidth issues and thought a dual LAN connection would solve the issue but I'd say most of those are WiFi related issues based on the network layout given. Fixing the network should correct the issues experienced, even if the OP needs to use WiFi they will just need to add additional WiFi networks/AP to fulfill the bandwidth need. This is not a dual NIC issue at this point from what I can see. I guess that if the OP truly needs up to 2Gb throughput, somehow they could configure a dual LAN setup however I'd think you would need a good managed switch to pull that off, but that still will not solve the WiFi limitations.
Gotta run, meeting family at the local Pizza joint, YUM!