The Celestron X-Cel LX eyepieces are very nice. Much better than the ones you have now. I would get a 7mm and a 40 mm.
I've got the 130 SLT and this is as about as strong as I'd go for the moon Celestron X-Cel LX Series Eyepiece - 1.25-Inch 7mm). Unless you want to zoom right in on individual craters I guess. https://www.amazon.com/gp/product/B0048JMGBU/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1
You can just barely get the entire moon in the eyepiece. Compared to cheaper eyepieces that come with the telescope, these are amazing. I've also got the 18mm version and it's great for taking cell phone pics of the moon.