You can download the patch from: http://www.uoex.net/codex/technical/startup
You can either download the entire prepatched client from the top of that page; or you can scroll down to the bottom and download only the updated files.
Once you are patched with 4b, you can go to the Patch Test Room in Town Center to check if you've installed it correctly. Once you enter the patch test room, there will be a sign a few steps north that indicates where the area for the 4b patch is. You should see the sign, bright green floors, and 3 items on the green floors (pictured below). If you don't see the floors and/or only see unused tiles where the items should be, you are not properly or fully patched. This patch includes a few hundred more wearables/graphics, over 50 new hues, map modifications for Elysium (Including 3 entirely custom dungeons built by yours truly), as well as a few tweaks and fixes from the previous patch. With this release, I'll be able to begin working on Elysium more actively again, and will be able to start releasing updated quest rewards

Enjoy!
- +N