When I need to execute a query with parameters I just create a PowerShell script for that specific purpose and load LibrarySmo at the beginning of the script. Here's a simple example.

param($au_lname)

$scriptRoot = Split-Path (Resolve-Path $myInvocation.MyCommand.Path)

. $scriptRoot\LibrarySmo.ps1

$srcServer = 'Z002\SqlExpress'

$qry = @"

SELECT * FROM dbo.authors

WHERE au_lname = '$au_lname'

"@

Get-SqlData $srcServer 'pubs' $qry

To execute save the code as a ps1 file (here I'm using getAuthor.ps1). You'll also need to change the $srcServer variable or add it as a parameter to script and pass the server name.

./getAuthor "White"

Also when I need to load the contents of a file such as a .sql file, I'll use the .NET ReadAllText method:

$qry = [System.IO.File]::ReadAllText("c:\users\u00\scripts\pubqry.sql")

As far Get-Help, eventually I plan on creating a proper snapin with Get-Help functionality in a future release.