$DBScriptFile = "C:\Scripts\RO_replication.sql" 
#SCRIPT
Invoke-Sqlcmd -ServerInstance localhost -database master -InputFile $DBScriptFile

USE MyDB{CountryCode}
GO
PRINT 'Adding articles to MyDB{CountryCode}_RO'
GO
exec sp_addarticle @publication = MyDB{CountryCode}_RO', @article = N'AdChannel', ...
GO
...

Select CountryCode From [DBUtilities].[dbo].[EnvBuild] Where Id = (select MAX(Id) from [DBUtilities].[dbo].[EnvBuild])

$DBScriptFile = "C:\Scripts\test.sql" 
$replacement = invoke-sqlcmd -query "Select CountryCode From [DBUtilities].[dbo].[EnvBuild] Where Id = (select MAX(Id) from [DBUtilities].[dbo].[EnvBuild])"
$Query = $DBScriptFile -replace "{CountryCode}",[string]$replacement[0]
Invoke -Sqlcmd -ServerInstance localhost -database master -InputFile $Query