id be interested in hearing more about what happened and the details of the car.
drivers airbag is easy, couple screws from behind. seatbelt pretensioners a bit longer bit straightforward enough. the passenger airbag is the kicker though. when that fires it effectively ruins the dash. did you get a replacement dashboard? they are cheap enough to buy, but the labour to change them out....
cant see any reference in elsawin to having to replace the module when replacing discharged airbags. would clear them with vcds after replacing the blown airbags.
mate of mine had a cat d rover with a blown drivers airbag, and the light on the dash, was fine until the mot rules changed. so we changed the bag, and had to change the module with a 'clean' module as there wasnt a way to clear the fault that we knew of. another friend's astra had curtain and seat bags blow on drivers side, we replaced the drivers seat and curtain airbag and wiped the fault with opcom, so id go with the vcds method rather than changing the module. elsawin mentions having to recode a replacement airbag control unit fwiw.
depending on the cars spec, age, mileage, id either attempt to repair it myself if i were you, or simply sell as is. the cost of getting outside help to repair it might make it financially unviable. any accident repair garage would be able to do the work though, no need to rely on retrofitters.