Um *cough*. The linked thread turned out to be an infected machine on the network sending out massive upload traffic and being accessed by out-of-country IPs. I certainly hope you're not running into the same issue, but you may want to run a full antivirus scan on all computers connected to the router... and may want to check what ports are showing traffic on your router.
We do have instances where a router failing causes intermittent connection problems, so you may want to try bypassing the router and just connecting directly with one PC for a while as a test. Not saying it IS your router causing the problem, but seeing if the problem remains with the router removed would prove if the problem is elsewhere.
If you need further help though, feel free to shoot me a PM with your account info.