O,

There are books in the library on home repair that will have door lock
information. There may be lock books as well. A phone call to a local
locksmith should give you an idea about what information you'll need to
bring down to get a replacement lock set. Most hardware store will have
common locksets so if you find one that matches your holes and seems to
match your lock set then it may be a good choice and the assembly
instructions should help you to dissassemble the old set.

Dave M