Combine the previous two answers. Suppose you were going to a vegetable stand and asking if they had tomatoes. "Have you tomatoes," would be extremely confusing to the person you were asking. "Have you got tomatoes," would be understood, but sounds incorrect and somewhat uneducated to my ear. "Do you have tomatoes," is by far your best option. I would use "do you have" in almost all cases, unless you hear someone using one of the others, then you can probably use it in the same context they did.

gonna = going to It's a way of expressing the future tense. It means something like "I will" or "I intend to." Example: I'm going to run to the store. [I will go to the store./I intend to go to the store.] I'm gonna download iTunes. [I will download iTunes./I intend to download iTunes.]

(Englisch ist meine Muttersprache.) Was Cherry gesagt hat, ist richtig. Ich möchte nur hinzufügen, daß Englisch schwieriger in Aussprache ist, weil die Schreibung nicht phonetisch ist.