YOU SAID:

I wish I could own a car.

INTO JAPANESE

私は車を所有なあ。

BACK INTO ENGLISH

I'd own a car.

INTO JAPANESE

私は車を所有したいです。

BACK INTO ENGLISH

I would like to own a car.

INTO JAPANESE

私は車を所有したいと思います。

BACK INTO ENGLISH

I would like to own a car.