You're best off talking to the civil engineering faculty head. The contact info for civ eng is jhe-301, 905-525-9140 x 24287. Hopefully thats the right place (got it from the website).
After that its a matter of meeting the admissions requirements (its harder to get into engineering if not applying directly out of highschool, and probably equally difficult if you're comming from another university/college). I don't know how reinstatement, but I would phone the registrar, some people on
this page, and that civ eng contact above maybe.
The reinstatement form is on
this page (not sure if you would be treated as a reinstate-ing person or whether you would have to apply to the program from scratch).
Good luck..