How are non-split sequences of this form?

Question

So, imagine we have $$0\to \mathbb{Z}_4 \to G \to \mathbb{Z}_{2^{n_1}}\oplus \mathbb{Z}_{2^{n_2}}\to 0$$ a short exact sequence that is not split. Then we know that $G$ is not a direct sum of $\mathbb{Z}_4$ and $\mathbb{Z}_{2^{n_1}}\oplus \mathbb{Z}_{2^{n_2}}$, but can we say that $G\cong \mathbb{Z}_{2^{n_1+2}}\oplus \mathbb{Z}_{2^{n_2}}$ or $\mathbb{Z}_{2^{n_1}}\oplus \mathbb{Z}_{2^{n_2+2}}$ or are there more possibilities?