PC Advice on Drafting/Gaming Computer

I been thinking about getting a new computer for myself since 1) I am going to ITT for Drafting and Design (finish next year, still undecided for BA Course) 2) Most of the games that I play is Windows type games (I got a 27 Inch IMac btw so I am dual booting).

This computer will be use for Drafting/Design/Gaming, while my other stuff will be on a MacMimi (Selling the IMac). I dont have any of the parts right now on me except for 2 1TB HDD that I use right now for my games and movies. I am willing to upgrade my computer and I just want to make sure that programs like AUTOCAD, PS and other work on there. My budget is 900 for right now (I can try to push it to 1200 if need). I am a newbie when it comes down to doing this but I am willing to learn and try to do it right.