If you can’t find the GW2 under ~/Library/Application Support/ you might have to enable hidden files/folders. Keep in mind GW2 is under ~/Library/Application Support/ and not /Library/Application Support/. To enable hidden files/directories just open up terminal and enter the following command..
defaults write com.apple.Finder AppleShowAllFiles YES
Then restart Finder.
To disable hidden files just do..
defaults write com.apple.Finder AppleShowAllFiles NO
Hope this helps.