Both cameras are USB cameras, is that right? Does the video for both cameras show up in the iCamSource windows correctly?
I'm not sure what you mean when you say both cameras need 70%. How much bandwidth are the two instances of iCamSource using? What are the symptoms of the problem you're experiencing? Are there any error messages on the computer or the iPod?
Since I don't have a good understanding of what problem you are experiencing, I'm not sure if a different wireless router would be any help. If you think the strength of the wireless signal is causing the problem, you can always check by moving the wireless devices (computer or iPod) closer to the wireless router. If everything behaves better in that situation, then the wireless signal strength might be the cause of your problem.