Go back into your router wireless settings.

Where it says "linksys", change that name to whatever you want.

You can also change the random list of numbers to a password(encryption key) you can remember. Remember to SAVE all your options.

WPA is the most secure setting, but WEP is fine.

If all else fails, call your internet provider and have them walk you through it. You're their customer, they should be willing to help.