OK, i did not get a chance to test this but try this script. You will have to change some of the OU= stuff and the wscript.echo things, but it should help get you in the right direction. You need to be able to query the AD for the Username. once you do that you can return the object.properties (or in this case 'department')
'create the strUsername to use later
Set objNetwork = WScript.CreateObject("WScript.Network"

strUsername = objNetwork.username
'Test it
WScript.Echo strusername
' put the strUsername in the query where it belongs
'
' (will have to change OU= and dc= values)
Set objUser = GetObject _
("LDAP://cn="& strusername &",ou=portal,dc=staging,dc=com"

objUser.GetInfo
strDepartment = objUser.Get("department"
'Test again
WScript.Echo strDepartment
'Mapping the Drive
if strDepartment = "Human_Resources" Then
Set net = CreateObject("WScript.Network"
net.AddWindowsPrinterConnection "\\Server\Printer"
Else
Set net = CreateObject("WScript.Network"

net.AddWindowsPrinterConnection "\\Server\Printer"
End if