Conflict of two wireless connections

Hi, here is my problem. I have an USB Wireless internet connection at home (USB adapter connects via mobile network). And I have standard Linksys wireless modem for within house IP cameras. Each connection works fine, but not both of them at the same time. As soon as Linksys modem (for IP cameras) is turned on, Internet connection fails. I use Windows 7 and standard Network and Sharing center does not even show wireless USB adapter, it appears only if I click on "connect to wireless network" option. Therefore I kind of do not have the way to set wireless USB adapter as an adapter for Internet connection. Any ideas how to deal with this will be appreciated.
Here is a question / problem update. Internet connection does not work also when wireless IP cameras are turned off (no any bandwidth issues). Looks like main problem is the router, if it is turned on - Internet connection fails, if off - connection establishes.