Welcome to the boards. Unfortunately, an AT&T phone can't be activated on the Verizon network. They use separate technologies ... GSM vs. CDMA. If you found a compatible BlackBerry, it would cost an extra $30 at this time (the data plan applies to each phone), although there are rumors that customers may be able to get a $15 data plan on smart phones in the future. It's unfortunate your boss takes all your upgrades. You could look on eBay for a Verizon phone and ask him to pony up.
That's a bummer, thanks for your help!