What's wrong with your PCM?
These days you'll need the original PCM to transfer things like unique ID's, VINs, and mileage to the new one because of theft issues.
If you just want an operational PCM without worrying about 'stolen vehicle flags' being raised at inspection you could get one from car-part.com or eBay. Cross-check the OEM part number on the PCM to the one you are buying, though, as there as usually multiple varients depending on engine/tran specifications