The version of mojoPortal in the Web App Gallery is usually a version behind the latest mojoPortal release because we have a short release cycle and there is a process to go through whenever we submit a new version to the gallery. You can upgrade over the version you installed from the gallery using the latest download from Codeplex. After upgrading, copy the files from /Data/skins to /Data/Sites/1/skins
Hope it helps,
Joe