。
If only I weren't poor, I'd buy a car.
Literal
Poor [if-not-なければ] car [object-を] buying [regret-のに].
The conditional なければ ('if not poor') paired with のに at the end expresses frustrated regret — 'if only X, then Y, but...' のに marks the unfulfilled wish with a tone of lament. A clear counterfactual conditional.