1997 Catera BCM

After several electrical malfunctions (door lockes, trunk release, etc.) I took 1997 Catera to dealer for checkup. $200 later I was told that I needed to replace the "BCM and relays." Only problem is that Cadillac no longer carries the part, and it is not available as an after market product. They advised me to donate the car to charity. They will not attempt a repair using a BCM obtained from salvage. Car also needs a new A/C unit and new passenger side headlight assemmbly due to broken adjustment tab - same problem I had on driver's side (cxost almost $400 to replace). Is it practical to consider attempting to repair this vehicle, and where should I go to try to find a mechanic qualified to do the work? Car has less than 75,000 miles and has ent-free, rust-free body.