Manny:  You can usually get a Krag cocking-piece for $10-20 on eBay or at a gunshow and 'salvage' your present bolt.  Original safety levers are also common.  You can google search S&S Firearms (Glendale, N.Y.) and look at their catalog on-line.  They have some original and reproduction Krag parts and are a good outfit.  (I am sure your present peep sight has some good salvage value and is worth researching).
   Your barrel should have two screw holes where the original military sight was mounted.  Sometimes these are filled with 'cut-off' screws.  These holes were spaced the same on all Krag models.  These holes with with their peculiar 8-26 thread can be salvaged.  Original sights are available at shows and on eBay.  S&S has some sights and reproduction screws.  Get the Poyer book as suggested.  I got mine on eBay (searching "Krag") for less than $20, including postage.  There are numerous models of Krag rear sights.  Some are quite rare and valuable.  There is a lot of fakery with Krag stuff.  Common sights are available and provide a solution on a Krag that has been ruined as a collector item but can still serve as a good shooter.  It would be interesting to see pictures of your Krag on KCA forum.  You might get some good help and suggestions.
                Regards -- Butlersrangers