On your non run days, do some cross training. Things like lunges, and squats (with out weights at first) will strengthen your butt, thighs, and hips to a degree. I think you will see an improvement within a few weeks. Lunge - 15 reps, 3 sets each leg. Squat - legs should be a little farther than shoulders, feet pointed out just a bit. same reps, and sets. Increase sets after a month to 5. Add 5lbs in each hand if you think you can keep good form. Intervals are good, yet once a week (in place of cross training) works well for me.
41 minutes is nothing to sneeze at, however, it you want to beat that- try x training. I run 4 times a week- 4miles tues. 3 miles wed. friday is my short run- one mile as fast as I can. Long run is Sunday- I am at 7. Each week I increase by 10 percent. Off days x train for 30-45 mintutes. Monday I do nothing- nothing at all but rest. Lots of stuff on runnersworld.com for this topic. Good luck, and keep it up.