Here's an example where a variable and an input box are used to select values smaller or equal than the variable. You should be able to figure out how to change it for your purposes.
AB.qvw 146.2 K
Is there any particular reason for using an input box to select the month number?
The normal Qlikview approach would to use a list box for month and the user would make the selection from the listbox. No need for macros and/or actions. But perhaps you have good reason for not using the standard approach?