It appears that checking MSI version in PowerShell is much less trivial than checking DLL version. Yet, the following script can do it for you. Most of the credits for the script go to this StackOverflow question.

###############################################################
# Name:         GetMsiVersion.ps1
# Description:  Prints out MSI installer version
# Usage:        GetMsiVersion.ps1 <path to MSI>
# Credits:      http://stackoverflow.com/q/8743122/383673
###############################################################
param (
    [IO.FileInfo] $MSI
)

if (!(Test-Path $MSI.FullName)) {
    throw "File '{0}' does not exist" -f $MSI.FullName
}

try {
    $windowsInstaller = New-Object -com WindowsInstaller.Installer
    $database = $windowsInstaller.GetType().InvokeMember(
        "OpenDatabase", "InvokeMethod", $Null,
        $windowsInstaller, @($MSI.FullName, 0)
    )

    $q = "SELECT Value FROM Property WHERE Property = 'ProductVersion'"
    $View = $database.GetType().InvokeMember(
        "OpenView", "InvokeMethod", $Null, $database, ($q)
    )

    $View.GetType().InvokeMember("Execute", "InvokeMethod", $Null, $View, $Null)
    $record = $View.GetType().InvokeMember( "Fetch", "InvokeMethod", $Null, $View, $Null )
    $version = $record.GetType().InvokeMember( "StringData", "GetProperty", $Null, $record, 1 )

    return $version
} catch {
    throw "Failed to get MSI file version: {0}." -f $_
}

Here is the execution sample:

C:\>powershell -ExecutionPolicy bypass -File GetMsiVersion.ps1 "C:\Program Files (x86)\Google\Update\1.3.21.79\GoogleUpdateHelper.msi"
1.3.21.79

C:\>

Enjoy!

Checking DLL version in PowerShell is extremely easy.

Here is the script that does it for you. Note that the real code fits in a single line (lines 17-18, I just split it out for readability). Other 20+ lines are dedicated to script header, input validation and exception handling.

###############################################################
# Name:         GetDllVersion.ps1
# Description:  Prints out DLL version
# Usage:        GetDllVersion.ps1 <path to DLL>
# Author:       Anton Khitrenovich, Jan 2014
###############################################################
param(
    [string]$DLL
)

if (!(Test-Path $DLL)) {
    throw "File '{0}' does not exist" -f $DLL
}

try {
    $version =
        Get-ChildItem $DLL | Select-Object -ExpandProperty VersionInfo |
            Select-Object FileVersion | Select-Object -ExpandProperty FileVersion

    return $version
} catch {
    throw "Failed to get DLL file version: {0}." -f $_
}

Here is the execution sample:

C:\>powershell -ExecutionPolicy bypass -File C:\GetDllVersion.ps1 "C:\Program Files\Java\jre7\bin\java.dll"
7.0.250.17

C:\>

Enjoy!