The latest version (of Twilight anyway) is 2.04 so if you're not seeing that you'll need to update. If your game is a digital download, it should automatically be updated by the service you downloaded it from. If it's a retail unit then you'll need to register your game's serial numbers to get updates from Stardock.
The Ultimate Collection/Edition should install both the expansions. If you've not got any shortcuts for the launchers, just go to the install folder and look in the Dark Avatar or Twilight directories for them. The install folder will vary depending on how you got the game - for example if you downloaded from Steam it'll be in the Steam programs folder as usual.
You should check out the Modding section of the forums as well, if mods are your cup of tea.
