Some thoughts...
1. Good for you for wanting to commute by bike!
2. Tires: I am a fan of panaracer pasela tourguard tires. They are a more puncture-resistant than many tires, so you should get fewer flats. With some looking, they can be had for $20-25 each (retail is about $30). They come in 26x1.75 and 26x2-either will work with your bike.
3. Flats: Get a spare tube, a flat kit, and a small pump you can carry along. If you are on a bus line (and the buses have bike racks) and are willing to wait for the next bus if you get a flat, you can skip the pump, and just fix any flats when you get home. I prefer to replace my tube when I get a flat, then patch it when I am back home. If you are unfamiliar with the process, there are tons of youtube videos that should be able to help you out. Practice a couple times at home, that way when you get a flat, it is raining, and you need to quickly change a tube to get to work on time, you can fly through it.
4. Racks: I took a look online at your bike, and a standard rack won't attach to it. However, there are seatpost-mounted racks that will. They have limited weight capacity, and you can't hang panniers off the sides of most of them. That said, you can use a couple bungies to strap on your backpack or a milk crate in which you put your backpack or other bag.

Good luck! You sound like you are off to a good start.