1. Why and how would you upgrade the game through Steam if it's done in game launcher?
2. This is your second thread about slow downloads, maybe the problem is on your side?
If the progress bar freezes or gets stuck when trying to patch, please try the following steps:
Open the launcher in administrator mode, you can do this by right clicking on the launcher and selecting "Run as administrator" from the drop down menu.
Go to game options. This is located in the middle of the launcher under the news feed.
Cancel any update in progress.
Return to game options and select settings.
In setting change auto update from always to never.
Press apply.
Select the cog wheel up the top right hand corner of the launcher.
Select the megaserver you want to change to ( EU or NA)
Once this is complete go back to game options and select check for updates. This should start to patch the game for your new server.
If it does not patch select repair from game options and wait for the repair to finish.
Once the repair has finished select check for updates.