Looking at those pics it actually doesn't look so that bad, you got a few options. Your floor is very flat so it would be very easy to repair. You should and out the rust and see how bad it is. If those couple of holes are all you got they would be easy to patch. Even the part of your frame would be pretty easy to fix. You would need to know how to weld though. If you don't already, I highly recommend taking a course at your local college. You would be able to fix it all during the course and would have some professional help along the way. Even if the rust is really bad, because the floor looks to be basically just a flat piece it would be super easy to cut out with a grinder and weld in a whole new floor. No need for a specific floor pan for your car. Then you'd just need to repaint it. You'd also learn some very valuable skills of you took a welding course. The other option is you can find a shell for your car on Craigslist that has already had all the body work done on it. That would actually be a lot more work though to swap every part of your car over though and your VIN numbers would no longer match, though I don't believe that is much of an issue on a 914. If you went that route though, I'd look for a Porsche 6 body and maybe a motor as well so you could have a much cooler car after all that work. So it really depends on how you want to handle it, if you want the upgrades it might be worth it to find a whole new car as well. It really doesn't look all that bad! Good luck!