Desktops :: CRT IMac Battery - Failing Fast

the PRAM battery clearly is failing fast. After two assurances from a large local computer seller/repairer (Best Buy) that they could indeed go to her apartment, and after acquiring the correct battery for her, I have now found out that they won't go to her apartment because the computer is more than six years old. Dead end there! Does anyone know of a place in New York City (or an individual) that would both visit her apartment and be sufficiently conversant with the innards of such an old Mac that there would be a good chance that the battery will be replaced without harming the computer? There doesn't seem to be anything wrong with it besides the failing PRAM battery, but Barbara is willing to pay handsomely to have her baby fixed, even if it means having the person go over it with a fine-tooth comb and charging accordingly. The computer is extremely heavy, or I'd take it in to the Best Buy store myself, and though we could get it into a taxi (with help from a doorman), there is the problem of getting it into the store and downstairs, where the repair area is. I'm strong but probably, not strong enough to do it, and we don't know anyone who could help. Any thoughts? There are multitudes of repair places and individual repairers in NYC, and many who visit people's apartments, but we clearly need someone who knows very old iMacs intimately and is not afraid to approach the problem.