UPDATE: Here's a good description of these exercises...you don't have to use a resistence band; weight of your leg will be hard enough if you do many reps.
http://www.ediets.com/news/article.cfm/2/code_22388/cmi_1...
Lunges are good = big steps forward, one at a time going across a long room..or backyard. Lunge forward with one foot --big forward step and stay there for a second or two and then step forward, feet together...then repeat across room several times.
http://en.wikipedia.org/wiki/Lunge_%28exercise%29 (for a pic)
Also...don't know if you go to a gym..but the leg press weight machine is great (good for leg quadriceps and leg hamstrings)! And there's also a leg abductor;leg inner-thigh weight machine (inner and outer thigh).
If you don't have access to weight machines....try this.....Hip/Leg Abductor exercise: stand up straight, hands on waist, and lift one leg to side (toes pointed forward, foot flexed flat)...slow, controlled movements up and down to your side...all on one side first. Try 3 reps of 10 first (take 1-2 min break in between sets if you need it). Do more if you can stand it.
And switch to other leg....
The balance will work the other leg at the same time...and your core muscles, too.
For inner thigh: standing, do the ballet pose/position, Plié: toes/feet pointed out. legs wide apart. And squat up and down - slow, controlled movements. And in another set: go down, half-way up, down, half-way up. So you never really get a break on the up. In another set: go down and stay down for 4 seconds, then up. Repeat for whatever # of reps you want.
Must stress this: stretch all muscles of the legs before and after you do this strengthening exercises.