If I go over my minutes can I get more for the month without committing to a long term plan?

I can see online that I am already going to be charged $13.80 for text messages above my limit and am just a few minutes to my calling minute limit. I have t-mobile - month to month plan but don't want to get locked into a long term contract. Is there anything I can do for this month to increase minutes/texts? I have T-Mobile.