BeagleBoard xM with ubuntu 12.04 and opencv slow with face detection

Hello, I have an issue and I would appreciate it if someone could help. I am running ubuntu 12.04 on a beagleboard xm. I have also installed opencv. Now I need to run an application which performs face, eyes and smile detection with a webcam. I am having a hard time with this because the image I get from the camera as well as the detection are very slow and exactly the opposite of real time. I know that probably I need a strongest hardware. My problem is that I am using this board for my thesis. My teacher gave it to me and now I am trying to find even the slightest improvement.