I note that no one else has given the OP any helpful replies to his question.
Just cant SEE why no ones pricing this work, its clear to SEE whats needed, just a boiler change.
someone called me about another 20 y.o. requiring a service which I declined and suggested that because it was old it would be better replaced with gas.
Why would you do that. No problem keeping oil boilers running.
That is if you knew how to work on them.