Find, strip, and replace assistance

I have a field that contains the following data

CN=Testuser, OU=TestOU, OU=Domain

I want to do the following:

1. If the record being passed into my step has TestOU, strip everything except for TestOU and input that value into a field already in the stream called "Company"
2. If the record being passed does not have TestOU, then do nothing to that record

I can't determine best step to accomplish this.