It sounds like you already have a strong application, so really now you can just focus on GRE and SOP. Additional language is definitely good if you aren't at a research reading level for the ones you'll need, but I think they'll mostly just focus on your undergraduate record and what you've already done academically. I took a 2 year gap between my MA and applying for PhDs (just finished the application cycle for that). I did nothing in those 2 years related to history or to improve my application and was successful, so having the gap didn't really seem to hurt at all.