loosening up the lower body



I've noticed that I'm having problems getting my feet to go where I like them to. For example, against even a moderate size opponent, I find it difficult to get my top leg over the guy's shoulder and into position for a triangle without a whole bunch of jockeying around. Getting my feet from my opponent's hips to up near his neck when in a butterfly guard is more of the same. Most silat holds are especially challenging for me for many of the same reasons. Anytime my legs are pushed back (kind of like the finishing position for a full barbell squat), I experience the problem. I can eventually do the holds -- I'd just like to be able to them quicker, and expending less energy.

I don't think my problem is strength here, but instead, flexibility. Have any of you guys faced this before, and if so, what do you do to gain flexibility in the hips and legs? What area of the lower body should I be focusing on if I want to remedy my problem? I'm thinking hips and hamstrings, but I'm not so sure.
When I first started I felt slow doing triangles and other moves like that but I never thought it was due to flexablity. After a few months and more drilling It went away. I would say just drill drill drill.
Thanks JDenz!

Any drills you can recommend for me to do alone? I train even on the days I'm not at my school, and on those days I'm without a partner. I have no problem training standup or weapons that way, but I'm not sure how to grapple without a partner and not have the guys in white coats show up. :D
No I don't know to many single person drills without spending 300 dollars on a dummy and even ten they arn't that good my advice is find someone from the school.