Can I Become A Bicycle Commuter??

Last summer, my goal was to go canoeing. I never managed to find the means or the company for such an excursion, but I did float down the Elbow River in Calgary, so I came close to realizing my dream. My goal this summer was supposed to be floating down the Pembina, but I'm busy most weekends with school, so that's become my backup summer goal.
My goal for this summer is to ride my bike to work. Sounds easy enough, right? I hosed the cobwebs and rust off my 15yr old Canadian Tire p.o.s bike, pumped up the tires, and took it for a 2min. test drive down the driveway. It still works. I bought a helmet, bell, lights and u-lock. I'm ready, right? I only work downtown once a week - that's do-able, right?
Except it's 12km from my home to my job at the court house. That's not the problem: the problem is I have to cross the Yellowhead freeway, and get through Chinatown (which is narrow enough as it is, and bordered on both sides by dodgyness). I figured it would take an hour, which I'm ok with, but friends have said it'll take more like 1.5 hours, which I'm not ok with. It's not like I'll ever ride late at night or in the rain, but a 3hr commute for a 5hr shift, just to save $5 on parking or bus is crazy, right?? I'm going to test out 1/3 of the route today, so we'll see how that goes. The things I'll do to save $5 and lose 10 lbs...
Any thoughts/comments/suggestions about how I can realize my dream are much appreciated!!