If you tried using the channel down to go below channel 2 and that didn't work then you are going to need a remote.
Some cable box remotes have a source button on them so if the code for your TV is in the remote that would turn on the TV and change inputs. Otherwise you would need a replacement for the original remote or a universal remote that has the correct codes. The Logitech Harmony remotes program from their online database so those should work too.