You must use Kirckhoff laws for alternate circuits. So, the tranfer function that you'll find can be used for any input signal, with Fourier Transform (because transfer function is the output of the system for a delta signal input in frequency domain).
We obtain:
$$\left\{\begin{aligned}
&V_I e^{i\omega t}= R (I_1(t)+I_2(t)) + j \omega L (I_1(t)+I_2(t))+ R I_1(t) \\
&V_I e^{i\omega t}= R (I_1(t)+I_2(t)) + j \omega L (I_1(t)+I_2(t))+ \frac{1}{j \omega C} I_2(t) \\
\end{aligned}\right. $$
or, if you aren't interested to know $I_1$ and $I_2$ in separated rings you can consider the parallel of R2 and C:
$$V_I e^{i\omega t}= RI(t) + j \omega L I(t) + \frac{1}{\frac{1}{j\omega L}+ j\omega C}I(t) $$
Now, you haven't sayed where is Vout...but with these approach, you can easily calculate current and tension in every point of circuit.