The main thing with squats is, are you pushing off of your toes, middle of your foot or heels? Where you push from, how wide your stance is and how deep you go will determine what you get out of them. For example, I used to do really high-bar style squats and push too much off the fronts of my feet - it made my quads grow like crazy, but my hamstrings and glutes didn't get much out of it. Once I widened my stance a bit, started going deep to well past parallel and would push off my heels instead of the fronts of my feet I could feel the unworked muscles getting into it more, and now my hamstrings and glutes feel the most sore after a good session. Experiment with different widths (I prefer just sightly wider than shoulder stance, but very wide works well for glute/ham recruitment as well) so it may just be that your form needs a bit of tweaking to get it down to where it will do the most good for what you're seeking.
If you decide to use a leg press (which I don't really recommend), try heels-only presses with the front half of your feet hanging off the platform - use only your heels to push off and it'll do more good for your needs than standard positioning leg presses. But, as it is known, I think that the leg press machines of the world should just be melted down to make more steel for 45 and 100 lb. plates as they'd do more good that way, so I'm not one to say much about those cursed things
Once I realized years ago that my being able to leg press 1300 lbs. for 5 reps didn't translate to being strong in any other movement made me lose all respect for those machines. Not to mention a few back injuries from the idiotic seat angles soured me a bit as well.
Anyway, getting a bit off track here. Squat, squat wide, squat deep, and push off of your heels and you'll get what you need!