Help with the Bb clarinet?

Ok well I started clarinet for my love of music and I started last November or October sooo Ive been playing for about 5 months and Ive practiced as much as I can. But I don't have anyone teaching me, but myself and a little bit from my band teacher and the other clarinet player. But it's notuch help. So I need help with trying to get a good sound, not squeaking; and trying to hit higher than the third octave C. I know you're supposed to get your muscles for your embouchere (or however you spell it) but I don't know how exactly. Oh and posture wise...do I hold my clarinet higher or lower? And I use a size 2 reed since I AM a beginner. My bad director said that was a good size to start on. Sooo yeah help?