Just to move this question from the Unanswered section - the Sextante plugin has been renamed to the Processing plugin.
And as of version 2.9.0, you can use the Select by expression tool (separately or within the graphic modeler) which allows you to select features based on the expression provided.
This can include multiple attribute values, for example:
"column_A" = 'X' OR "column_B" = 'Y'
