Can I extend the amount of time before I am "timed out"?

You can't customize the amount of time of inactivity before the system logs you out. That is set to four hours of inactivity. Typically, though, we see people working on something as a financial or group admin in one tab and then in another tab be working on something like a registration link, giving link or response to an email which would be a member level access. In this case, you are essentially logged in at 2 different levels in the same browser. When this happens, the browser automatically changes the login level to the lowest one. So, if you go back to try to do something, you are logged out of the higher level.

The solution is to make sure you are doing things at the same login level in a browser. If you check something like a registration link, open up a new browser and bounce back and forth between them.