No i understand that you only have One Exchange Server.
Create another Database on your Exchange Server.
Even in Exchange 2007 STD you can create 5 Databases (Stores).
EMC -> Server Configuration -> Right Click on your Storage Group -> Create a New Database.
http://technet.microsoft.com/en-us/library/bb201716(EXCHG.80).aspx
Then move the Mailbox to this New Database you have created.
http://www.msexchange.org/articles_tutorials/exchange-server-2007/management-administration/moving-mailboxes-exchange-2007-part1.html
See if you are able to see the Public Folders from Outlook