A typedView is a dataTable, and there is no special ways in LLBLGen to filter a TypedView in memory.
Here are your options.
Option #1:
You can use something like this to filter a dataTable:
Dim rows as DataRow() = myTable.Select( "name like '%Mary%' order by LastModifiedTime" )
ref: http://www.dotnetspider.com/kb/Article614.aspx
Option #2:
Re-fetch from the database (filter on the database side).
Option #3:
Use an entityCollection from the start, which gives you the advantage of using an EntityView to filter its content in the memory.
Needless to say you can map an entity to a database view.