Windchill and Creo Advance Use help.

Hey Guys
I'm back with a new requirement. I have designed/modeled 5 parts with standard part numbers and description and assembled them in xxx. Now assuming these parts are standard parts and are already released in windchill. I want to write a program which will search the existing parts in windchill according to the description or any other criteria and replace these 5 modeled parts in to my assembly xxx.
Please help me save my job.
Looking forward for experts to reply.

Thanks