You can try to get Canasa through the Canasa Care program:
http://www.canasacare.com/
The other option that has helped me through really bad times is ordering from Canada. The prices there are so much better and they have generics available for a lot of the drugs we don't have generic for here.
I was just like you when I got diagnosed with proctitis. I had the somewhat frequent bathroom trips with blood and mucus but other days, I would be next to normal (doesn't sound like you have the normal days so much)... I would see blood with every movement but it would range from a drop on the tp to a little on the stool, never a lot of blood.
Are you having a lot more blood than this? I don't remember having trips to the toilet with just blood until my condition had deteriorated past the point of being managed with suppositories. It is my recommendation that if you're not seeing improvement with the suppositories that you go to a GI and find something that will help you. If you allow your body to stay in this flare, not only will it most-likely continue to get worse, you could end up at elevated risk for colon cancer. Not trying to scare you but we, people with UC/UP, have to be much more dilligent about our colon health.
Please go get checked out. You may need oral meds or rectal enemas to stop the inflammation. UP can turn into UC. A bad flare will not be managed with Canasa. Mine wasn't anyway...