Where can I get a Roku game control?

[mickeys friend]

Where can my sister get a remote control that works with her Roku? She said she's looked on their site and only saw the ones that come with a new Roku.We have a new one that had the games included and it has a game controler with it.She has a Roku with a remote,but not the game one.I know I saw someplace that had them for sale without buying a new Roku,but I can't remember where.Any help would be great.Thanks