Retina-ized menulet icon?

[Fofer]

Minor issue, I know... but the resurrected GrowlVoice's is the sole remaining menulet icon in my toolbar that doesn't have Retina-ready resolution. And so it is blurry and ugly.

Is there a way for us to be able to replace the menulet icon with a 2x resolution one?

The relevant files I see in /Applications/GrowlVoice.app/Contents/Resources may be:
GVMenuletIcon.png
GVMenuletIconInverse.png
GVMenuletIconMute.png
GVMenuletIconMuteInverse.png
GVMenuletIconMuteNoConnection.png
GVMenuletIconMuteUnread.png
GVMenuletIconNoConnection.png
GVMenuletIconUnread.png