Right now I am having a really hard time finding details of that title just by punching "カラフル☆きゅあ~ 楽しみディスク" into Google. Generally that doesn't happen so... yea, a little more detail next time would be nice as it might go a long way into tracking your request.
Btw some more info related to your requested title. Though it's probably not exactly what you are looking for since you mentioned an Append Disk, about which btw I am seeing no info whatsoever, but here are some more details regarding the original game. Maybe others who wanna help you can use that to track down your request faster.
Original Title: カラフル☆きゅあ~
Romaji Title: Colorful☆Cure
Release Date: 2012-06-05
Company: Etoiles
Getchu: http://www.getchu.com/soft.phtml?id=734639 [You can see the "imouto" character you mentioned among the line of characters displayed so I am pretty positive about the title.]
VNDB: http://vndb.org/v9909
Unfortunately I couldn't find any info on Append Disk. Either it does not exist or it's called something else entirely and we are off track.
Could you please re-upload;
[050922][月面基地前] 月面基地前プレミアムBOX Vol.1 ロケットの夏編 [+コンプリートサウンドトラックス] ?
The main-disc link is alive. I need only "Complete Soundtracks".
Sorry, but RG doesn't work for me.