Eduardoh wrote:
In what sense of the phrase do you want it? (Not spanish here. Portuguese. But I know some spanish, cause I live near argentina and uruguay)
If it is like "Get Back! Dont come any closer!", than the translation would be something like that "Te aleja! No te acercas!"
If it is something like "Get Back! I wanna talk to you.", than it would be like this "Vuelve aca! Quiero hablar con te."
If is in any other meaning, please ask.

Hope it helps (and that some spanish speaker shows up to correct me, or confirm it

)
I'm afraid I have to correct you

(BTW, I'm from Spain)
You almost got it right. The correct way of doing the translation would be "aléjate", not "te aleja", but depending on the context, a better translation would be "¡Atrás!" (notice the first exclamation mark, as is written in Spanish) or "¡Vete!".
Greg, if you give me the context, I can provide with the exact translation. Also, if you need more help with Spanish dialogue, feel free to ask (if you prefer, my email is davidbarrenaATyahooDOTes).
Un saludo,
David