Extracting an assembly from the GAC...

...can easily be done without the need of a third party tool.

Here's how:

1. Open the Windows Explorer and map a new network drive.
2. Map to the GAC folder on you machine, e.g.: \\YOURMACHINE\c$\windows\assembly

Voila - that's it.
You can now open the newly added network drive and copy out the assemblies from the GAC.