Exchange 2010 Powershell Script to create distribution list

Hello Totally New at the scripting.  But i'm trying to make a script so our help desk can create distro group with emails without having to connect to the exchange server it self, and only having them use a powershell script. Below is the script that i came up with, but having a bit of an issue trying to get it to work. As i am not sure how i can get  return the switch result in to a variable.  

This is exchange 2010.  Thanks for helping out in advance.



$DistributionGoup = Read-Host -Prompt 'New Distribution Group Name ( No Spaces)'
$Alias = Read-Host -Prompt 'Enter Alias Name'

Write-Host Please Pick The Domain From The Following List
Write-Host 1. CB Domain
Write-Host 2. TB Domain
Write-Host 3. PS Domain
Write-Host 4. GB Domain
Write-Host 5. TC Domain

$domain = Read-Host -Prompt "Domain"

switch ($domain)
{
1 {"cb.smbmi.local/distribution Groups";break}
2 {"tb.smbmi.local/distribution Lists";break}
3 {"ps.smbmi.local/distribution Groups";break}
4 {"gb.smbmi.local/distribution Groups";break}
5 {"tc.smbmi.local/distribution Groups";break}
default {"No Domain Determined."}

}


new-DistributionGroup -Name $DistributionGoup  -OrganizationalUnit $domain -SamAccountName $DistributionGoup -Alias $DistributionGoup