I have attempted to split this into partial fractions of the form $\frac{A}{(z-1)} + \frac{B}{(z-2i)} + \frac{C}{(z+2i)}$ as well as by $\frac{A}{(z-1)} + \frac{Bz+C}{(z^2+4)}$, but things get very complex (ha!) with i's and z's showing up in the numerator. How should I proceed?
I am told to find the series about 0 and 1, taking into account the different values of the radii.
Hint: use the limits $\lim_{z\to 1} (z-1)f(z) = \frac{1^2}{1^2+4}$ and similarly $(z-2i)f(z)$ for $z\to 2i$ and $(z+2i)f(z)$ for $z\to -2i$. Also note that $C = \overline B$ formally.