Well you really didn't "lose a car". Sure, it was a dick move on the salesperson's part. But look at the opposite viewpoint. You put a deposit but didn't sign a contract. Someone came in willing to buy it immediately and commit. So the salesperson, wanting to make a living, went ahead and sold the car. From his perspective, if you could have decided against purchase, backed out, and requested your $1000 be returned. You hadn't signed a contract, and the other buyer did.
So I see his viewpoint. Was it a dick move? Sure, but he wants to make a living and can't live off Maybe's.
Reason I suggested the General Manager was he might be accommodating given the situation, and try to bring in another vehicle to once again make you happy, and generate another sale. If I were in charge, that'd be my objective. Far as the salesperson goes, can always work with another one as I stated.
Seems too bad though, this dealer doesn't seem motivated to accommodate your request to bring in another vehicle, now that the one you wanted is gone.