Hello Karthik,
We would not be having information on 2nd Hand Compressor dealer shops in Bangalore
You may have to check out with Spare Part or Scrap Dealers for same for Compressor available for accidental cars.
Used compressor with AC Gas filled in between Rs 5K to 7K in Maruti Cars. AC Gas, fitting, Expansion Valve etc are generally Rs 3000 - Total cost could be around Rs 10K - based on negotiation and condition.
In terms of Repairs - Generally. Authorized Workshops advise for replacements and do not perform repairs.
In terms of brand new compressor assembly (Could be Subros or Sanden Compressor been used in Swift) along with fitment, AC Refill, Labor - can cost in atleast Rs 30K including Labor. Assembly Part includes - Compressor, AC Condenser, Valve, Evaporator - all gets changed.