You can indeed download all your software from the MyAccount page.
Once you renewed in August, which was after the sale of Impulse to GameStop, Impulse became unusable for SD desktop application management. You may leave it on your system if you wish and if you created archives of your apps - you will still be able to restore those archived apps using Impulse in the unlikely event you ever need to, but you'll only be able to restore those on the OS on which they were created. If it were me, I'd only keep Impulse installed if you plan to use it for Gamestop purposes.
Odds are you'll never need to restore prior versions of anything, so download all the installers from the MyAccount page & back them up. To avoid any potential glitches, I'd uninstall all the current software using Impulse* and then run CCleaner (or similar) to clean up any remnants. Be sure to unload WindowBlinds & any of the other running SD apps before you uninstall.
Once your system is clean again, you can run the new installers you downloaded. You'll be prompted for your current registration key via an Activation dialog when you first run any of the newly installed apps.
I know it sounds like a lot of trouble, but it's probably best to get things 'clean' for the future.
HTH
*I'm not 100% clear on whether Impulse will uninstall apps after a renewal has been processed, but I think so. Maybe Zubaz will see this and confirm one way or the other.