Brake Calipers on A6 4.2 Quattro

Hello All,
Could anyone help me with a problem. I have a 2001 A6 Avant 4.2 SE Quattro that the gearbox ECU failed on. The car went to a local garage who kept it for 8 months without fixing it as I was hoping to get a secondhand/reconditioned ecu. I went to collect it and the front calipers have seized on so now I’m looking for replacement ones but if possible secondhand, refurbished or non oem parts as the car’s value doesn’t warrant huge expenditure. Alternatively if anyone would like to buy it from me then that’s possible too. Many thanks

Thank you for your reply, sorry for the delay but the present situation has prevented me from responding. I have been offered a set of good working calipers from a same year C5 S6 V8, will they fit my car??? I did look at the the calipers repair kit but the garage that has my car said they had tried that route but weren’t able to free the calipers at all !