A/C compressor needs replacement.
 

Ok So I noticed a noise from my engine when parked, kinda like a box of screws being rattled, it seemed to happen when the AC was turned on...

My mechanic told be that it was the a/c compressor and advised me to save up....

So from what I understand the have changed the aux belt and bypassed the a/c pully, hence no A/C.

My question is, can the a/c unit be repaired and if what type do I need to order.

My Car is the 2004 A4 1.9 tdi multi-tronic.

Any help would be great.