Also looking at the engine pic it looks like you've got manual brakes, so switching to power brakes would help a lot. If you've got drum all around as well, that would explain having to really push hard on it. As for the brake pedal going to the floor, that sounds like air in the brake lines, contaminated fluid, or, the proportioning valve could be way off. Check your master resevoir level to see if its low and look for bubbles as well. If everything is fine, bleed the rear brakes again, and see if fluid comes out fine, or if nothing comes out..a kink in a line. If everything checks out, Id lean towards proportioning valve problem.
There isn't any proportional valve on it(see pic). Which is normal for not having front disk brakes. Also, manual drum brakes that are working right do not work how you have described these. It sounds like you either have just front or just rear brakes. Which is very dangerous because you are half way to having no brakes at all. Trouble shooting will start at the master cylinder to check on fluid levels for your first clue. The clue will be which chamber is low. This will narrow down the search for trouble. Second clue would be the wet spot somewhere.
