Hi Julie,
In this case, you'll want to apply a date filter (which can either be a 'row' or 'column' filter depending on data). In this case, you'll want to use a column filter, given the months are appearing in the column headers.
Step-by-Step directions are here:
Steps to apply a date filter
Note: Apptio is sometimes stubborn with the format it expects to see in the column headers. I typically recommend customers use 'Jan','Feb','Mar', ext, as the column headers. I've had a few instances where we've also added (similar to what you've done, 'Jan-16', 'Feb-16') and Apptio does seem to recognize the year and does filter appropriately.
Hope that helps,
Justin