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Several steps could improve your attempt:

• Produce more keypoints, e.g. by lowering the threshold for SURF or by chosing a different keypoint detector.
• Filter your matches via cross-check / ratio-check (you'll find them in this forum if you search for it).
• And finally, the most important: Compute the transformation matrix (i.e. homography matrix via RANSAC) between the matched points and check if the transformation is valid at all, i.e. in your case there should be nearly no rotation/scale/shear.

If this still doesn't help you, you can also try simple template-matching (see http://docs.opencv.org/modules/imgproc/doc/object_detection.html?highlight=matchtemplate#matchtemplate) or, more advanced, train a classifier, e.g. a cascade-classifier w. a texture-feature like HOG/LBP/HAAR (OpenCV provides you all the necessary tools to create your training-set and so on, see http://docs.opencv.org/doc/user_guide/ug_traincascade.html and http://docs.opencv.org/doc/tutorials/objdetect/cascade_classifier/cascade_classifier.html#cascade-classifier and the various topics in this forum).

Good Luck!