If the chatbox is still viewable and you can type in it, type /re 960 540 (you can change the numbers to however you feel comfortable with, following the L.H format).
If you aren't able to type this for whatever reason, you will have to visit your toribash directory and alter default.cfg.
To do this: My Computer << Local Disk (C:) << Games << Toribash v.## << open 'default.cfg' with notepad << edit the lines of resolution (height and width) << save the document.