A chihuahua is probably not the best bet if you want to take him to work with you. They tend to be more territorial, barky and nippy.
Yorkies make great lap dogs, and in my experience are not as yappy as a lot of other toy breeds. (Then again, each individual dog has it's own personality!)
I absolutely say adopt/rescue! So many "breeders" are actually puppy millers (and back yard breeders) whose does are only bred for money, are over priced and often have health issues.
You can check
Search results - pets in adoption centers near Clayton, NC
for a start in available yorkies. Contact local rescues and shelters to see what is available there as well!
I'm a major advocate for rescue. So many wonderful dogs are in need of homes!