Most of the Disney hotels have game arcades for guest entertainment. Each of these has a dozen or more coin-op type games that cost a dollar or two. These are a fun place to pass a few minutes on a rainy day.
However, what I think you are referring to in your question is
DisneyQuest, the indoor interactive theme park located at Downtown Disney. This is five floors of electronic entertainment, ranging from large DanceDanceRevolution-type games, computer animation stations, and design-your-own-rollercoaster simulators. Prices can change, but the current one-day admission price approximately $40.00 for adults and $35.00 for children.
As to the "would a five year old girl like it" question, that depends a lot on the girl and her interests. I took my girls to DisneyQuest when the twins were six. At the time, they had not much experience with arcade-type environments. They found DisneyQuest to be loud and overwhelming. I will also tell you that there are height restrictions for some of the attractions here that unless your daughter is super-tall she is unlikely to make.
If you feel that the "boys" would be better off on their own at DisneyQuest, there are plenty of nearby alternatives for you and your daughter. There is a beautiful AMC movie theater steps away from DisneyQuest. Plus, you're also right at a GIANT shopping and dining area. There are many fun restaurants for a "ladies lunch." You could also take your daughter to the Downtown Disney Bibbidi Bobbidi Boutique for a princess makeover. You won't be lacking for entertainment options if you split up for a few hours.