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 The graph of a quadratic function passes through three points A, B, and C, where point A is at (-l, 0), point B is at (3, 0), and point C is located on the negative half of the y-axis, with OB being equal to OC.
(1) Find the analytic expression of this quadratic function:
(2) By how many units to the right should this quadratic function's graph be shifted so that the shifted graph passes through the point (1, 5)? Also, determine the coordinates of the intersection between the shifted graph and the y-axis.