First question: what operating distance does Linksys specify for this device?
There are many reasons that could be the cause of the signal not leaving the room (e.g., the materials in the walls prevent signals, other external interference, etc.) However, if it is struggling to make it across a small, empty room, it could be equipment failure on one of the ends. Have you done any hardware troubleshooting such as trying another access point or computer in the room to see if one of those items fixes the problem?