Sorry, I get all wrapped up in new information on drivers - and I end up losing track of what we were doing!
The device manufacturer's sell that device to several different PC manufacturer's - so Toshiba may decide to support Win7 while the other manufacturer's don't. If that's the case, then the only place to get the drivers (for Win7) will be Toshiba.
Where did you get the information that this is a Bush product? I wasn't able to find any computer products made by "Bush" in my internet searches.
It's always a good idea to uninstall the drivers before installing the new one's. This helps to eliminate problems that the installer may not be able to cope with.