You're on the right track when considering the crush of your grains. You could have the LHBS run the grain through twice, but I suggest getting your own adjustable mill. After I got my mill, I went from low 60's to 75-80% efficiency.
I was stuck at 65% also before I bought my BarleyCrusher. I'm now at around 77% for 1.050(ish) beers.
Something else to maybe consider is mash length. After a failed attempt a few months ago to brew a IIPA when the gravity came up short. I took some advice I read here on the forum about mash length and mash out temp. I'm a batch sparger as well. I brewed a Black RyePA(?) yesterday and I'm proud to report I made the biggest beer to date w/o the use of brewing sugars. 1.077 OG at 68% eff. I'm not sure if it had anything to do with it but I did a 90min mash and attempted to mash out but only got my grainbed up to 163F.