I got a 164, but 14 of the 21 missed questions were from logic games.

From others' experiences, are logic game scores fairly easy to improve? Just so I get a long-term picture, what do you think a 164 cold scorer can typically achieve with a good few months of studying? Is the 173+ needed for HYS reasonably out of the picture?
I can't afford an LSAT class so I'd be using the Powerscore bibles for studying. Any other good tips for a guy just starting LSAT practice and wanting to keep costs down?
Thanks