pomofo,
Now is not the time to get really concerned about the cost of repair.
It may not take as much as it looks like now. You can take it one part at a time, from maybe different sources. I have a tipup German rifle that had one leg of the top lever spring broken. As a "make do" fix, I just jammed a leaf from another broken spring into the "V". That was 25 years ago and I have used it since, even killing deer with it. Your problem might not be that simple, but it might. This is sort of a standard spring anyway and I think Dixie Gun Works may some in stock( 2or3 types). The photo showed the right hammer missing, if you don't have it, that may be a problem to "match", but one that "works" can likely be found. The oil soaked wood can be a problem. I suggest you check closely for loose coming ribs and cracks in the action, these can be insurmountable problems, if they exist. If you don't insist on a re-finish to "factory new", you will save a lot of money. From the photos, you might have a pretty unusual type of drilling. It has exterior hammers but the selector is not common for hammer drillings. This leads to the possibility that the rifle fires from a separate hammer on the trigger plate. I suggest you join the German Gun Collectors Assn. and buy reprints of a series of articles by John Laborde, discussing different drilling types. I think I would be pretty excited to have it. Try to make clear photos of all the markings, even if you have to have help.
Mike