Norton Equivalent Circuits in PSpice?

Alright lads, i'm having awful trouble with some study i'm doing for an exam on monday, and despite my best efforts, i can't figure out a circuit. Well, i can, but i get a different answer to my lecturer's. So i tried simulating it on pspice, and i get a completely different answer with that again!!!

So the answer i get on paper is 2.42 amps.

His answer is 2.91 amps

and my pspice answer is 1.091 amps!!!!

Obviously i'm doing this completely wrong somewhere, so could someone please help me!

I'm not very good at the electronics end of my course (i'm specialising in civil engineering next year) so don't abuse my incompetence!

Cheers,

Stephen