After Parvo it take a long time for them to snap out of it. I would put her on a bland diet for a few weeks like rice and hamburger or chicken. Her intestines need time get back to normal and probiotics will really help. Check out this website it is the best for treating dogs that have parvo but also on how to help them recover from it.
Home Parvo Treatment ~ Healing Parvo Puppies ~ Page 1
I would not feed the canned food because the kind you were getting is not the best quality and no wonder the poor thing got the runs. The appetite will come back as time goes on with your puppy.
Some dogs recover fully and some are never the same, I hope your pup can fully recover!