Steam automatically updates. You wont need to uninstall. We recommended beta testers uninstall today before they update to the new version just to clear out any lingering junk that we've around around in all our various betas and verisons. From here on out it updates and you are set.
Every update will be made available to everyone, regardless of how they got it (steam, impulse, direct, etc). Steam players will get it automatically, direct customers will download and install a patch.
You cannot transfer your key from direct to steam (or to another digital retailer).
