Remotely Querying a key on all user's registry on multiple machines

basically what I want to do is run a query on all machines within an IP range to find a registry key from each user on each machine, all the machines are on a domain which I have domain admin on

it would be best if I could write these to a .csv file or similar 

this is what i have so far, it's currently running by wildcard on machine name, but that won't get all machines i want and may get some outside of the range I need (192.168.3.0-192.168.3.255)

$server='mex'[a-z0-9]*
$key ='SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings'
$regKey = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey('Users', $server)
$regKey = $regKey.OpenSubKey($key)
$p = $regKey.GetValue('ProxyOverride')

I think i can export using this

http://powershell.com/cs/forums/t/16862.aspx