Ok, I think I see where you want to go.
For the filename of the CSV, you could just update the line where you compose the name of the file.
Something like this
$VC=Connect-VIServer$VCServerName
$ExportFilePath="C:\PS\Export-$($VCServerName)-VMInfo.csv"
If you have multiple vSphere server connections open when you call this script, you could add the Server parameter on the PowerCLI cmdlets.
That way the cmdlet will only return results for that specific vSphere server.
Something like this
Get-VM-Server$VCServerName