If the vid cable, and its logic board connector are both damaged (and the connector does not look good), then both will need to be replaced.
I don't know if the cable can be replaced without replacing the LCD assembly, too.
Between the LCD, and the logic board - you will probably get close to the cost of another MBAir.
Or, maybe you will get lucky, and a good cleaning of the connectors might fix. I don't have any confidence in that, and it WILL depend on luck.
You said that you had this checked out already. What did they tell you about the cost for repair?
The only help that I can provide, is to suggest that you consider spending the money to get it repaired properly, or sell this one for parts.
(Liquid spills usually do not end well. Now you know ...
)