Wait a minute, wait a minute.
There is no webOS v.4
If you have the original Pre or Pixi or the Pre+/Pixi+, you have webOS 1.4, if you have a Pre2, a Veer or a Pre3, it's webOS 2.x and the Touchpad comes with 3.x
webOS Quick Install, what you are most likely referring to, is an installer app that is used to load Preware on your device, and from Preware you download any other homebrew app.
Depending on your device, you can still upgrade the OS version using MetaDoctor, but that's tricky if you aren't careful and you may end up bricking your device. Don't tell me i didn't warn you.
Ok, i see you have a Touchpad. That most likely runs the most recent version available