Answer
The source is moving toward you at 0.220c.
Work Step by Step
The Doppler effect shifts the frequency of the source, due to its motion.
The source is moving toward you, because you perceive a higher frequency.
$$f=\sqrt{\frac{c+u}{c-u}}f_0=1.25f_0$$
$$ \sqrt{\frac{c+u}{c-u}}=1.25$$
$$ u=\frac{1.25^2-1}{1.25^2+1}c$$
$$u=0.220c$$