The perfective is better here. Already is usually a key word for the perfect.
I find the stress on продал a wee bit weird. Should it be on the а and not the о? Shouldn‘t it be продал and not продал?
As far as I know, according to the actual orthoepic rules the stress should be on the "o" (it also sounds more pleasant to my ears), but the form with stressed "a" is admissible as well. This means that the form with stressed "a" has not established as a correct one yet, but it might happen in the perspective :)
It is funny to see how different this is treated in the English for Russian speakers course. There they insist that уже is a marker for past perfective and that the word уже itself doesn't need to be translated in the English sentence. There the correct translation would be: Tom had sold his car.
It's his own car he has sold, not someone else's. Danish and Norwegian and probably Swedish also have this, and it's a convenient way to differentiate between two potential meanings. And Esperanto has this, too, but only in the 3rd person unfortunately.
I know it is basic question but I still don't understand why not using "его" instead of свою.
I posted my answer here, but it seems to have replied to another comment above. Weird.