Engineering Grad vs Undergrad

[confused23]

Hey guys,

                 I'm currently finishing up my Junior year as a MechE major at UC Berkeley. I am pretty keen on going to grad school to study Mechatronics or Information Systems(not exactly engineering but comparable i guess). The only thing that really discourages me is that I have a lowish GPA here(3.3 with a slight inflation due to humanities courses). Assuming I am able to get into a grad school(USC, Purdue or schools of similar or calibre), I am very concerned about whether I will be able to maintain a 3.5+ gpa there(I've heard most companies prefer that grad students maintain at least a 3.5). I work pretty hard to do slightly above average at Berkeley, and I'm afraid it's severely affecting my confidence about my potential grad school performance(I know this sounds a little naive but hey).

I was wondering if someone could give me any insight into what grading is like in engineering grad schools? Are the curves just as harsh? Is there anything I can do to better prepare for the workload?

Any advice would be appreciated